Category Archives: Blog post

This World Rabies Day, the International Companion Animal Management Coalition urges governments around the world to adopt and strengthen the One Health approach with a clear and unmitigated focus on mass dog vaccination for eliminating rabies by 2030 – the United Nations Sustainable Development Goal target that all member states signed up to.

Every year 59,000 people die from rabies and millions of dogs are inhumanely culled in a misguided attempt to stop the spread of rabies. We know that killing dogs does not stop the disease. Removal of dogs through culling or for consumption undermines rabies control efforts. Indiscriminate culling and removal of dogs inadvertently targets the more accessible vaccinated dogs and brings down vaccination coverage (the number of vaccinated dogs as a proportion of the total dog population). It destabilises the population leading to a younger population of rabies susceptible dogs and leads to public upset and resistance against rabies control.  What works is mass dog vaccination – the only efficient and proven way to eliminate rabies.

Humane Dog Population Management (DPM) can further contribute to rabies control by reducing unwanted or unmanaged dogs and reducing population turnover, keeping vaccination coverage high and therefore achieving herd immunity (when enough of the population is resistant so the virus cannot spread and dies out) to protect dogs and people. DPM is important to sustain the gains of mass dog vaccination.

Efforts to eliminate rabies not only has an impact on bite cases and mortality, but also a psychological impact, changing perceptions of dogs from animals to be feared to companions. Therefore, by eliminating rabies through mass dog vaccination, animal welfare and the treatment of dogs will also improve in addition to the human health benefits.

The ongoing global COVID-19 crisis has highlighted the interconnect between animal, human, and environmental health. The significance of the One Health approach to address current and future challenge cannot be overstated – with multiple sectors and stakeholders stepping outside their silos to collaborate towards common health goals. Rabies elimination is the perfect example of One Health in action – a focus on dog health that saves the lives of people and the enormous financial burden of this disease.

Rabies, despite being one of oldest known zoonotic diseases, continues to be one of the major public health problems in around 150 countries around the world. This is the disease that impacts the poorest countries and the poorest communities within them. Truly a disease of poverty that needs to be consigned to history books.

Search for an event or register your own World Rabies Day event on the GARC website.

Join the webinar on Monday September 28

Join the WSAVA’s 2 part webinar on September 28 to mark this year’s World Rabies Day. Bringing together stakeholders and experts, including the OIE, GARC and World Animal Protection to discuss the importance of humane management and animal welfare in the global fight against rabies.

Read ‘All eyes on dogs’

Read World Animal Protection’s ‘All eyes on dogs’ report on why dogs hold the key to rabies elimination. And what actions stakeholders must do to achieve the goal of ending human rabies by 2030.

Download the report in English, Portuguese/Português, Spanish/Español, Thai/??? or Mandarin/???.

About International Companion Animal Management (ICAM) Coalition

ICAM supports the development and use of humane and effective companion animal population management worldwide. The coalition was formed in 2006 as a forum for discussion on global dog and cat management issues.

Our key goals are to:

• Share ideas and data
• Discuss issues relevant to population management and welfare
• Agree definitions and hence improve understanding
• Provide guidance as a collegial and cohesive group

Contact information: info@icam-coalition.org

Twitter: @ICAMCoalition

Those of us who work with companion animals will be all too aware of zoonotic diseases. These are diseases that are passed between animals and people, including rabies. Using vaccination and deworming to prevent these diseases in dogs and cats, and therefore also protect people, is a constant drive within our work.

COVID-19 is different. There are competing hypotheses for where it originated, including transmission from animals (possibly bats or pangolins) to people, we may never know the truth. But since the original ‘case zero’ in Wuhan, China, the transmission appears to have been entirely person to person. Except we have seen the odd rare case of SARS-CoV-2 infection in companion animals. Importantly, all these cases suggest the transmission was from an owner to their pet and not the other way; the person is sick, and some days later their animal shows similar signs or is tested positive during quarantine by public health officials. ‘Reverse zoonosis’ is a relatively rarely used term in companion animals but may be suitable with COVID-19. This is where an animal is the victim of a disease hosted by the human population; it has become infected, but it is not infectious. 

Infected: Can dogs and cats be infected by SARS-CoV-2?

Since the outbreak of the COVID-19 pandemic we have seen a number of positive cases in companion animals (see our blog on why testing in companion animals should be limited). But equally as important, are the negative results. The following is a summary of both. See the footnote for an explanation of the different diagnostic tests used¹:

Pets in homes with COVID-19 tested using RT-PCR:

Studies of infection in real-world samples:

Studies of infection in the laboratory:

Studying infection in a laboratory involves inoculation of animals with virus. Two laboratory-based experimental studies have produced the following results; Shi et al (2020) in China and Halfmann et al (2020) in USA/Japan.

These studies involved placing large doses of virus onto susceptible tissues deep inside nasal passages, mouths and eyes; this may be very different to the viral loads and exposure experienced in the real-world. The type of laboratory animals used and the way they are kept may also contribute to reduced immunity. Hence, ICAM advises caution in applying the results of such experimental studies to real-world disease control. These studies may be more suited to comparing responses between species or individuals within the confines of the study.

Infectious: Can dogs and cats transmit SARS-CoV-2 to other dogs and cats? 

There is no real-world evidence of transmission between animals, on the contrary, some of the positive cases mentioned previously lived with other animals that tested negative. However, there is evidence of transmission between cats from the two laboratory-based studies mentioned previously (Shi et al 2020 and Halfmann et al 2020). These studies exposed naive animals (animals that had not been infected with virus) to inoculated animals to see if these naive animals would then ‘catch’ the virus.  

• Shi et al. 6 pairs of inoculated and exposed cats were housed in neighbouring cages. The exposed cats in 2 pairs had positive results for PCR and antibodies, the other 4 exposed cats were negative. The same scenario with 2 pairs of dogs showed the exposed dogs had no positive test results. This suggests that transmission between dogs is not possible, but transmission between cats might be possible. 
• Halfmann et al repeated this study but just with 3 pairs of cats who were co-housed in small cages. They found all 3 exposed cats became infected. None of the cats showed symptoms and there was no evidence of viral shedding after 5 days. 

As described above, these laboratory-based studies have limitations when extrapolating to real-world disease control. In addition to concerns about viral loads and immune system health, these pairs of cats were kept in constant close proximity in small cages. ICAM believes these factors in experimental studies combine to increase the chances of infection far higher than would occur in the real-world between pets or roaming animals.

Negative test results from real-world infections also provide some evidence that transmission between animals may not be occurring: 

• The German Shepherd in Hong Kong that tested positive for SARS-CoV-2 also lived with a mixed-breed dog that repeatedly tested negative. 
• The cat in New York, USA from a COVID-19 home lived with another cat that tested negative.
• The Pug in North Carolina, USA lived with another dog and cat, neither tested positive for SARS-CoV-2.
• The cat in Germany lived in a retirement home with her owner who died of COVID-19, two other cats that lived in the same home tested negative.

In each of these real-world scenarios is a test of potential transmission between animals AND from people to animals, as they were all in the same household with people who were sick with COVID-19. That transmission did not occur is evidence that sick owners infecting their pet is not inevitable, it appears to be very rare. It also suggests transmission is not occurring between animals.

Infectious: Can dogs and cats transmit SARS-CoV-2 to people? 

“Currently, there is no evidence that animals are playing a significant epidemiological role in the spread of human infections with SARS-CoV-2.” OIE. Evidence of transmission from dogs or cats to people would require clarity on two factors; timing and other transmission routes. A person would need to become sick with COVID-19 after their dog or cat had shown signs of infection AND all other possible routes of transmission from people would need to be excluded. Because they are in contact with many more dogs and cats than most people, veterinarians and shelter workers would be most at risk for this kind of transmission. Thankfully, there appears to be no greater prevalence of COVID-19 in these workforces. 

With over 4 million human cases worldwide we have an abundance of complex, uncontrolled but undeniably valuable epidemiological evidence about transmission. The extremely small number of infections from people to dogs and cats, and the lack of any examples of transmission to people, is meaningful. Dogs and cats are not playing a role in transmission of SARS-CoV-2 to people. These companion animals are the victims of this reverse zoonosis; they are (rarely) infected but not infectious.

Footnote 1: What testing methods are available for companion animals?

In the majority of cases, the tests offered for companion animals will be RT-PCR tests for viral genetic material. The following explains this test and its limitations in more detail and two other tests that are being used for companion animals, usually in research contexts:

• RT-PCR: Uses oral, nasal or fecal/rectal samples. Amplifies available genetic material so is very sensitive. However, a positive test doesn’t prove the virus is live, just there is viral genetic material there, which can occur after live virus has been cleared or if there have been contamination of the animal or sample by viral particles. Need to show persistent positive RT-PCR results to show an active infection. 
• Virus isolation: This attempts to culture (grow) live virus from swabs, so a positive result implies there is an active infection and there may be a chance of infectiousness, although this depends on viral ‘load’ (amount of virus) and closeness of contact.
• Serology: Uses blood samples to test for the presence of antibodies. A positive result proves there was infection at some point. However, antibodies are slow to become detectable, so not the best markers for active or acute infection. 

Resources

• AVMA 
  • Summary of SARS-CoV-2 animal cases 
• OIE
  • Questions and Answers on the COVID-19
• Worms and Germs blog

About International Companion Animal Management (ICAM) Coalition

ICAM supports the development and use of humane and effective companion animal population management worldwide. The coalition was formed in 2006 as a forum for discussion on global dog and cat management issues.

Our key goals are to:

• Share ideas and data
• Discuss issues relevant to population management and welfare
• Agree definitions and hence improve understanding
• Provide guidance as a collegial and cohesive group

Contact information: info@icam-coalition.org

Twitter: @ICAMCoalition

Los que trabajamos con animales de compañía sabemos perfectamente qué son las enfermedades zoonóticas. Estas son enfermedades que se transmiten entre animales y personas, por ejemplo, la rabia. La vacunación y la desparasitación para prevenir dichas enfermedades en perros y gatos—y, por lo tanto, para también proteger a las personas—es una preocupación constante en nuestro trabajo.

El COVID-19 es diferente. Existen hipótesis opuestas sobre dónde se originó, por ejemplo, el contagio de animales (posiblemente murciélagos o pangolines) a personas, pero puede que nunca sepamos la verdad. Sin embargo, desde el “paciente cero” original de Wuhan, China, pareciera ser que el contagio haya sido completamente de persona a persona. Como excepción, hemos visto el extraño caso de animales de compañía contagiados con SARS-CoV-2. Cabe señalar que todos estos casos indican que el contagio fue de un amo a su mascota y no al revés; la persona se enferma, y algunos días después, su mascota presenta síntomas similares o los funcionarios sanitarios públicos le hacen una prueba que da positivo. La “zoonosis inversa” es un término que rara vez se usa en los animales de compañía, pero podría aplicarse al COVID-19. Esta se produce cuando un animal es víctima de una enfermedad sufrida por la población humana; es contagiado, pero no tiene capacidad de contagiar.

Contagios: ¿Los perros y los gatos pueden contagiarse de SARS-CoV-2?

Desde el brote de la pandemia de COVID-19, hemos visto varios casos positivos en animales de compañía (visite nuestro blog para saber por qué las pruebas en animales de compañía debieran ser limitadas). Sin embargo, los resultados negativos son igual de importantes. A continuación se presenta un resumen de ambos. En la nota al pie podrá ver una explicación de las distintas pruebas de diagnóstico utilizadas¹:

Pets in homes with COVID-19 tested using RT-PCR:

Estudios de contagios en muestras del mundo real:

Estudios de contagios en laboratorio:

El estudio de los contagios en un laboratorio implica inocular el virus en los animales. Dos estudios experimentales llevado a cabo en laboratorio han producido los siguientes resultados: Shi et al (2020) en China y Halfmann et al (2020) en Estados Unidos/Japón.

Estos estudios colocan grandes dosis de virus en tejidos susceptibles ubicados en el fondo de las fosas nasales, lo cual podría diferir mucho de las cargas virales y de la exposición que se experimentan en el mundo real. El tipo de animales de laboratorio utilizados y la forma en como son mantenidos puede contribuir a una inmunidad reducida. Por ende, ICAM aconseja precaución a la hora de  utilizar los resultados de estos experimentos en control de la enfermedad en el mundo real. Estos estudios sirven más para comparar respuestas entre especies o individuos dentro del marco del estudio.

Contagios: ¿Los perros y los gatos pueden contagiar el SARS-CoV-2 a otros perros y gatos?

No hay evidencia de transmisión entre animales, de hecho, algunos casos mencionados anteriormente que salieron positivos vivían con otros animales que salieron negativos. Sin embargo, sí hay evidencia de transmisión entre gatos en los dos estudios experimentales mencionados arriba de (Shi et al 2020) y Halfmann et al (2020). Estos estudios expusieron a los gatos no inoculados (que no había sido infectados con el virus) con gatos inoculados a ver si los no inoculados se enfermaban con el virus.  

• Shi et al. Se colocaron animales inoculados (6) en jaulas adyacentes a las de animales no inoculados (6) para ver si dichos animales se contagiarían al ser expuestos a un animal inoculado. De los 6 pares de animales inoculados y expuestos, 2 pares de gatos dieron positivo a la PCR y a anticuerpos, y los otros 4 gatos expuestos dieron negativo. El mismo escenario con 2 pares de perros reveló que los perros expuestos no dieron resultados positivos. Esto sugiere que no es posible el contagio entre perros, pero que tal vez fuera posible entre gatos. 
• Halfmann et all repite este estudio pero solo con 3 pares de gatos que se les puso en jaulas pequeñas. Los tres gatos expuestos se infectaron . Ninguno de los gatos presentó síntomas de la enfermedad y no había evidencia de diseminación del virus después de 5 días. 

Como se describe más arriba, estos estudios hechos en laboratorio tienen sus limitaciones a la hora de extrapolar la información al control de la enfermedad en el mundo real. Además de las preocupaciones por las grandes dosis de virus y la salud inmunológica, estos gatos fueron mantenidos en proximidad y en jaulas pequeños. ICAM considera que estos factores que se combinan en eperimentos de laboratorio  pueden aumentar la probabilidad de infección a mucho más de lo que se lograría en el mundo real con mascotas o entre animales deambulantes.

Los resultados negativos de los contagios del mundo real también entregan evidencia de que no existe contagio entre animales: 

• El pastor alemán de Hong Kong que dio positivo a SARS-CoV-2 también vivía con un perro de raza mixta que dio negativo varias veces.
• El gato del hogar con COVID-19 de Nueva York, EE. UU. vivía con otro gato que dio negativo.
• El pug de Carolina del Norte, EE. UU. vivía con otro perro y otro gato, ninguno de los cuales dio positivo a SARS-CoV-2.
• El gato en Alemania vivía en una residencia de ancianos con su dueña que falleció de COVID-19, los otros dos gatos que vivían en el mismo hogar salieron negativos.

En cada uno de estos escenarios del mundo real, existe la posibilidad de contagio entre animales y de personas a animales, ya que todos se encontraban en el mismo hogar junto a personas infectadas de COVID-19. El hecho de no haberse transmitido la enfermedad constituye evidencia de que el contagio de los amos enfermos a sus mascotas no es inevitable, pero parece ser muy inusual. También indica que no existe contagio entre animales.

Contagios: ¿Los perros y los gatos pueden contagiar el SARS-CoV-2 a personas?

“Actualmente, no existe evidencia que indique que los animales cumplan un papel epidemiológico significativo en la propagación de contagios humanos de SARS-CoV-2” OIE. Respecto a la evidencia sobre el contagio de perros o gatos a personas, sería necesario aclarar dos factores: el tiempo y otras vías de transmisión. Una persona tendría que enfermarse de COVID-19 después de que su perro o gato haya presentado síntomas de contagio, y sería necesario excluir todas las otras vías posibles de contagio de personas. Puesto que están en contacto con muchos más perros y gatos que la mayoría de la gente, los veterinarios y los trabajadores de los refugios correrían el mayor riesgo ante este tipo de contagio. Por suerte, pareciera no haber una mayor prevalencia de COVID-19 en estos trabajadores.

Con casi 4 millones de casos humanos en todo el mundo, tenemos una gran cantidad de evidencia epidemiológica compleja, no controlada pero innegablemente valiosa sobre el contagio. La cantidad extremadamente baja de contagios de personas a perros y gatos, y la falta de ejemplos de contagio a personas, resulta significativa. Los perros y los gatos no cumplen un papel en el contagio del SARS-CoV-2 a personas. Estos animales de compañía son víctimas de la zoonosis inversa; son contagiados (rara vez), pero no tienen capacidad de contagiar.

Nota al pie 1: Métodos de detección para animales de compañía

En la mayoría de los casos, las pruebas para animales de compañía son pruebas de RT-PCR que buscan material viral genético. A continuación seexplica esta prueba y sus limitaciones en mayor detalle así como otras dos pruebas que están siendo usadas en animales de compañía, usualmente en el contexto de investigación:

• RT-PCR: Se utilizan muestras orales, nasales o fecales/rectales. Esta prueba amplifica el material genético disponible, por lo que es muy sensible. Sin embargo, un resultado positivo no indica que el virus está vivo, solo que existe material genético viral, el cual puede encontrarse después de haberse eliminado el virus o por contaminación del animal o de la muestra con partículas virales. Es necesario contar con resultados RT-PCR positivos persistentes para demostrar una infección activa.
• Aislamiento del virus: Se intenta cultivar el virus vivo a través de hisopos, por lo que un resultado positivo indica que existe una infección activa y que podría existir la probabilidad de contagiosidad, aunque esto depende de la “carga” viral (la cantidad de virus) y de la proximidad del contacto.
• Serología: Se utilizan muestras de sangre para detectar la presencia de anticuerpos. Un resultado positivo indica que en algún momento hubo una infección. Sin embargo, los anticuerpos tardan en ser detectables, por lo que no son los mejores indicadores de una infección activa o aguda.

Referencias y recursos

• AVMA 
  • Summary of SARS-CoV-2 animal cases 
• OIE
  • Questions and Answers on the COVID-19
• Worms and Germs blog

About International Companion Animal Management (ICAM) Coalition

ICAM supports the development and use of humane and effective companion animal population management worldwide. The coalition was formed in 2006 as a forum for discussion on global dog and cat management issues.

Our key goals are to:

• Share ideas and data
• Discuss issues relevant to population management and welfare
• Agree definitions and hence improve understanding
• Provide guidance as a collegial and cohesive group

Contact information: info@icam-coalition.org

Twitter: @ICAMCoalition

The chance of an owner infecting their pet dog or cat is very low, however it is possible. Hence we predict that as cases of COVID-19 in people continue to occur, so the cases of companion animals will also continue to appear. These animal cases may be inevitable, but they are no cause for additional concern. These are cases of people infecting their pets, there is no evidence that dogs or cats play a role in subsequent transmission to people. 

As testing for SARS-CoV-2 in animals becomes possible in more countries¹, we make a plea to the veterinary community to limit their use. Positive test results have no impact on how vets treat symptoms as there are no specific treatments for SARS-CoV-2 in animals. However there is a significant risk of causing unnecessary fear in owners and communities from the media attention each positive case brings. So let’s keep testing resources for controlled and meaningful research studies and for testing for virus in people, where the real risk of transmitting SARS-CoV-2 lies. 

Should dogs and cats be tested?

Routine testing of animals is not recommended (e.g. CDC and AVMA). There is only evidence of transmission of SARS-CoV-2 between people and, in very rare cases, from people to companion animals. There is no evidence of transmission from companion animals to people. These companion animals are the victims of this reverse zoonosis (a disease transmitted from people to animals); they are infected but not infectious.

There are no treatments available for COVID-19 in animals, beyond only symptomatic relief. Hence there is no clinical relevance of testing for the individual animal. 

Bringing an animal to a veterinary clinic for testing brings the owner and vet into contact. This would be considered necessary if the animal is seriously unwell and there are ways of reducing the potential transmission risk during the consultation. However, cats and dogs infected with SARS-CoV-2 appear to have no to very mild symptoms, so in-person consultation for their health and welfare is unlikely to be necessary. 

The current advice for households with people suffering COVID-19 is to self-isolate all members of the household, including pets, and to avoid close contact with people and pets when you have symptoms. As any pet infected with SARS-CoV-2 will have caught the virus from their owners, a positive test result for pets is not required for making a self-isolation recommendation, it will have already been made in relation to the owners suffering from COVID-19. However, if the pet has been removed from a house where its owners were suffering from COVID-19, in an abundance of caution, it should be kept isolated from unexposed animals and handled minimally for 14 days (AVMA).

Although the regents used for testing for SARS-CoV-2 in animals and people are different, and hence there is no competition for these consumables, the PPE and swabs required when collecting samples are the same. Hence there is the potential for animal testing to impact negatively on testing capacity for people.

How to decide whether to test or not?

Whether testing of an individual animal should take place should be a One Health decision, including both human public health and animal health officials (OIE). Vets are encouraged to speak to their local health authority for help with making this decision. 

In addition, IDEXX note the following three criteria must be met:

1. Pet is living in a household with a human who has COVID-19 or has tested positive for the SARS-CoV-2 coronavirus
2. Pet has already been tested for more common infections, which a veterinarian has ruled out
3. Pet (especially cats and ferrets) is showing clinical signs consistent with COVID-19

Structured research into SARS-CoV-2 prevalence in animal populations is a valuable use of testing capacity. In such studies, animals are carefully selected for testing and contexts are carefully controlled or measured to ensure maximal information can be drawn from each test. Negative test results are equally valuable to positive and should be published. 

What are the consequences of a negative or positive test result?

Before considering testing a companion animal for SARS-CoV-2, there must be a clear understanding of the consequences of both a negative and positive result.

Negative result: 

• Inform the animal owner; how and what will you tell them?
• It is extremely likely that a negative RT-PCR means the animal does not have SARS-CoV-2. 
• However, a negative result could occur from an error in the way samples were taken or handled.
• Negative results are just as valuable as positive and should be recorded and reported with the same care and attention. 

Positive result: 

• Inform the animal owner; how and what will you tell them?
• There is no clinical significance for the animal, as there is no specific treatment for SARS-CoV-2. 
• An infection of an animal with SARS-CoV-2 is considered a case of an emerging disease and hence must be reported by veterinary authorities to the OIE along with information about the animal, diagnostic test and context. Vets must collaborate with their veterinary authority to establish clear and rapid reporting of test results.
• Because RT-PCR is sensitive to the presence of small amounts of viral genetic material, and doesn’t require there to be live virus present, it does not necessarily imply infectiousness. There is also no evidence of animals infecting other animals outside experimental conditions, and no evidence of transmission from companion animal to person. Hence a positive result does not imply isolation of the animal in addition to the isolation already being imposed on the owners and their household if they are sick with COVID-19. When an animal is moved from a COVID-19 household for care elsewhere, in an abundance of caution, 14 days of isolation from unexposed animals and minimal handling is advised (AVMA), no testing is required to action this recommendation.
• A positive result is very likely to attract media attention. This has the potential to cause unnecessary fear for animal owners and communities living with free roaming animals. As they may not understand the limited implications of this positive result. In extreme circumstances, this could lead to abandonment of pets and retaliation against free roaming companion animals 

Footnote 1: What testing methods are available for companion animals?

In the majority of cases, the tests offered for companion animals will be RT-PCR tests for viral genetic material. The following explains this test and its limitations in more detail and two other tests that are being used for companion animals, usually in research contexts:

• RT-PCR: Uses oral, nasal or fecal/rectal samples. Amplifies available genetic material so is very sensitive. However, a positive test doesn’t prove the virus is live, just there is viral genetic material there, which can occur after live virus has been cleared or if there have been contamination of the animal or sample by viral particles. Need to show persistent positive RT-PCR results to show an active infection. 
• Virus isolation: This attempts to culture (grow) live virus from swabs, so a positive result implies there is an active infection and there may be a chance of infectiousness, although this depends on viral ‘load’ (amount of virus) and closeness of contact.
• Serology: Uses blood samples to test for the presence of antibodies. A positive result proves there was infection at some point. However, antibodies are slow to become detectable, so not the best markers for active or acute infection. 

Resources

• AVMA 
  • Interim recommendations for intake of companion animals from households where humans with COVID-19 are present
  • ‘Handout: Testing your pet for SARS-CoV-2’, available on the COVID-19: AVMA resources webpage
• OIE
  • Questions and Answers on the COVID-19

About International Companion Animal Management (ICAM) Coalition

ICAM supports the development and use of humane and effective companion animal population management worldwide. The coalition was formed in 2006 as a forum for discussion on global dog and cat management issues.

Our key goals are to:

• Share ideas and data
• Discuss issues relevant to population management and welfare
• Agree definitions and hence improve understanding
• Provide guidance as a collegial and cohesive group

Contact information: info@icam-coalition.org

Twitter: @ICAMCoalition

Es muy poco probable que un amo contagie a su perro o gato doméstico; sin embargo, es posible. Por lo tanto, predecimos que seguirán apareciendo casos de animales de compañía contagiados a medida que continúen los casos de COVID-19 en humanos. Puede que los casos animales sean inevitables, pero no deberían causar mayor preocupación. Estos corresponden a casos donde las personas contagian a sus mascotas, aunque no existe evidencia que demuestre que los perros o los gatos puedan posteriormente transmitir la enfermedad a las personas.

A medida que aumenta la cantidad de países que pueden realizar pruebas de SARS-CoV-2 en animales¹, le pedimos a la comunidad veterinaria que limite su uso. Los resultados positivos no afectan la manera en que los veterinarios tratan los síntomas, ya que no existe un tratamiento específico contra el SARS-CoV-2 en animales. No obstante, existe un riesgo importante de infundir temor innecesario en los amos y las comunidades debido a la atención mediática que genera cada caso. Entonces, debemos destinar los recursos de detección a estudios de investigación controlados y significativos, así como a la realización de pruebas del virus en personas, que es donde se encuentra el verdadero riesgo de transmisión del SARS-CoV-2.

¿Se debería hacer pruebas en perros y gatos?

No se recomienda hacer pruebas de rutina en animales (CDC y AVMA). Solo existe evidencia de que el SARS-CoV-2 se transmite entre personas y, en casos muy raros, de personas a animales de compañía. No existe evidencia de que el virus se transmita de animales de compañía a personas. Estos animales de compañía son víctimas de la zoonosis inversa (una enfermedad que se transmite de personas a animales); son contagiados, pero no tienen capacidad de contagiar.

No existe un tratamiento disponible contra el COVID-19 en animales, solo un alivio sintomático. Por ende, hacer pruebas en animales no tiene relevancia clínica.

Llevar a un animal a una clínica veterinaria para someterlo a una prueba hace que el amo y el veterinario entren en contacto. Esto se consideraría necesario si el animal se encuentra en estado grave y existen maneras de disminuir el riesgo de contagio durante la consulta. Sin embargo, los gatos y perros contagiados con SARS-CoV-2 parecieran tener síntomas muy leves, o incluso no tenerlos, así que es poco probable que una consulta presencial sobre su salud y bienestar sea necesaria.

La recomendación actual para las familias con integrantes que padezcan de COVID-19 es aislar a todos los integrantes de la familia, incluidas las mascotas, y evitar el contacto directo con personas y mascotas si presentan síntomas. Como cualquier mascota contagiada con SARS-CoV-2 habrá contraído el virus a través de su amo, no es necesario que las mascotas den un resultado positivo para hacer una recomendación de aislamiento, pues ya se le habrá hecho esa recomendación a los amos que padezcan de COVID-19. Sin embargo, si se ha retirado una mascota de una casa cuyos propietarios padecieran de COVID-19, como medida de precaución, esta debe mantenerse aislada de otros animales no expuestos, y el contacto con dicha mascota debe ser mínimo durante 14 días (AVMA).

Si bien los reactivos que se usan para hacer las pruebas de SARS-CoV-2 en animales son diferentes, y por ende no existe competencia para dichos insumos, los equipos de protección personal y los hisopos necesarios para tomar las muestras son los mismos. Por lo tanto, es posible que las pruebas en animales perjudiquen la capacidad de hacer pruebas en personas.

¿Cómo decidir si hacer una prueba o no?

La realización de una prueba en un animal debe ser una decisión “One Health” (una sola salud), que incluya a funcionarios públicos de salud animal y salud humana (OIE). Se recomienda a los veterinarios que hablen con su autoridad sanitaria local para que los ayuden a tomar esta decisión.

Además, IDEXX señala que deben cumplirse los siguientes tres criterios:

1. La mascota vive en un hogar con un humano que tiene COVID-19 o que dio positivo al coronavirus SARS-CoV-2.
2. Se han hecho pruebas de infecciones más comunes en la mascota, que han sido descartadas por el veterinario.
3. La mascota (principalmente gatos y hurones) presenta síntomas clínicos consistentes con el COVID-19.

Las investigaciones estructuradas sobre la prevalencia del SARS-CoV-2 en poblaciones animales son una herramienta valiosa para evaluar la capacidad de hacer pruebas. En dichos estudios, se realiza una selección minuciosa de los animales que serán sometidos a la prueba, y los contextos son controlados o medidos de forma cuidadosa para asegurar que se obtenga la mayor cantidad de información a partir de cada prueba. Los resultados negativos son igual de valiosos que los positivos, por lo que deben publicarse.

¿Cuáles son las consecuencias de un resultado negativo o positivo?

Antes de considerar la posibilidad de hacerle una prueba de SARS-CoV-2 a un animal, es necesario entender a cabalidad las consecuencias de un resultado negativo y positivo.

Resultado negativo:

• Informar al amo del animal; ¿cómo y qué se le dirá?
• Es sumamente improbable que una RT-PCR negativa indique que el animal no tiene SARS-CoV-2.
• Sin embargo, un resultado negativo podría ser erróneo debido a la forma en que se tomaron o manipularon las muestras.
• Los resultados negativos son igual de valiosos que los positivos, por lo que deben registrarse e informarse con el mismo cuidado y atención.

Resultado positivo:

• Informar al amo del animal; ¿cómo y qué se le dirá?
• No existe relevancia clínica para el animal, ya que no existe un tratamiento específico contra el SARS-CoV-2.
• El contagio de un animal con SARS-CoV-2 se considera un caso de enfermedad emergente y, por ende, las autoridades veterinarias deben informarla a la OIE, así como facilitar información sobre el animal, la prueba diagnóstica y el contexto. Los veterinarios deben colaborar con su autoridad veterinaria para establecer una forma clara y rápida de informar los resultados de las pruebas.
• Como la RT-PCR es sensible a la presencia de cantidades pequeñas de material genético viral y no requiere que se encuentre presente el virus vivo, no necesariamente indica contagiosidad.
• Tampoco existe evidencia de que los animales contagien a otros animales fuera de condiciones experimentales, ni tampoco evidencia de que los animales de compañía contagien a personas. Por lo tanto, un resultado positivo no implica el aislamiento del animal, además del aislamiento que ya se haya impuesto a los amos y a su familia en caso de que padezcan de COVID-19. Si se traslada un animal desde un hogar con COVID-19 a otro lugar para su cuidado, como medida de precaución, se recomienda aislarlo de otros animales no expuestos durante 14 días, así como tener un contacto mínimo con dicha mascota (AVMA). Además, esta recomendación no exige la realización de pruebas.
• Es probable que un resultado positivo genere atención mediática. Esto podría infundir temor innecesario en los amos de los animales y en las comunidades que viven con animales vagabundos, ya que puede que no entiendan las implicancias limitadas de dicho resultado positivo. En circunstancias extremas, esto podría provocar el abandono de mascotas y represalias en contra de los animales de compañía sueltos.

Nota al pie 1: ¿Qué métodos de detección se disponen para los animales de compañía?

En la mayoría de los casos, las pruebas que se ofrecen para los animales de compañía son pruebas RT-PCR de material genético viral. A continuación se explica de manera más detallada esta prueba y sus limitaciones, así como otras dos pruebas que se utilizan en animales de compañía, generalmente en contextos de investigación:

• RT-PCR: Se utilizan muestras orales, nasales o fecales/rectales. Esta prueba amplifica el material genético disponible, por lo que es muy sensible. Sin embargo, un resultado positivo no indica que el virus está vivo, solo que existe material genético viral, el cual puede encontrarse después de haberse eliminado el virus o por contaminación del animal o de la muestra con partículas virales. Es necesario contar con resultados RT-PCR positivos persistentes para demostrar una infección activa.
• Aislamiento del virus: Se intenta cultivar el virus vivo a través de hisopos, por lo que un resultado positivo indica que existe una infección activa y que podría existir la probabilidad de contagiosidad, aunque esto depende de la “carga” viral (la cantidad de virus) y de la proximidad del contacto.
• Serología: Se utilizan muestras de sangre para detectar la presencia de anticuerpos. Un resultado positivo indica que en algún momento hubo una infección. Sin embargo, los anticuerpos tardan en ser detectables, por lo que no son los mejores indicadores de una infección activa o aguda.

Recursos

• AVMA 
  • Interim recommendations for intake of companion animals from households where humans with COVID-19 are present
  • ‘Handout: Testing your pet for SARS-CoV-2’, available on the COVID-19: AVMA resources webpage
• OIE
  • Questions and Answers on the COVID-19

About International Companion Animal Management (ICAM) Coalition

ICAM supports the development and use of humane and effective companion animal population management worldwide. The coalition was formed in 2006 as a forum for discussion on global dog and cat management issues.

Our key goals are to:

• Share ideas and data
• Discuss issues relevant to population management and welfare
• Agree definitions and hence improve understanding
• Provide guidance as a collegial and cohesive group

Contact information: info@icam-coalition.org

Twitter: @ICAMCoalition

A new publication by biologist Xuhua Xia of the University of Ottawa is the latest in a string of theories put forward by scientists investigating the origin of SARS-CoV-2. This theory proposes the intestines of dogs could have provided a place for evolution of the ancestor of SARS-CoV-2 into a ‘fully ready’ virus capable of the current COVID-19 pandemic. However, this theory relies solely on inference from virus genome structures and there is no actual evidence of dogs as the origin, or that dogs are playing any role in current virus transmission. COVID-19 is a disease spread from person to person and this publication does not change that. 

ICAM emphasises that this is not evidence of SARS-CoV-2 transmission risk from stray dogs to people and in no way justifies stray dog removal or culling.

Xia himself states that such measures “commits unjustified brutality against these dogs.”

ICAM again strongly urges everyone, particularly global media outlets to exercise caution; to be responsible and not use alarmist headlines whilst reporting and sharing information on this issue.

Xia has mourned the “many misunderstandings in news articles with misleading titles that distorted what I said in the paper.”

Xia makes several leaps and assumptions in developing his theory about dogs and he, and many other scientists, have proposed other competing hypotheses. In the absence of any real world data this current theory regarding dogs should be treated with extreme caution. 

Indeed, where actual samples have been collected from dogs and cats, SARS-CoV-2 is overwhelmingly not being found. IDEXX Laboratories has evaluated thousands of samples, in the US, South Korea, Canada and Europe, including areas with high rates of COVID-19 in people, and have seen no positive results. A study of pets in close contact with COVID-19 patients in France also reported all negative results when testing for virus infection (Temmam et al 2020). Although two dogs in Hong Kong were found to be positive, the presence of the virus was only ‘weak-positive’ and transient before tests returned negative results; being infected does not mean an animal is infectious, that requires a sufficient amount of live virus in tissues that are open to contact. Furthermore, many other dogs and cats tested in Hong Kong all returned negative results.

For pet owners and people living in communities with stray dogs, this publication needs to be put  in perspective when considering current risk. Xia notes that the original “zoonotic (a disease shared between animals and people) transmission must have been a very rare event”. It’s extremely likely that this happened only once and since then the transmission has been entirely person to person. Animals are not part of the current transmission risk to people. 

Our advice remains to simply avoid close contact and practice good hygiene with pets, especially if you have symptoms of COVID-19. These precautionary measures will keep your pets safe from the virus. 

Xia’s theory specifically talks about feral dogs. He describes SARS-CoV-2 appearing in people as a ‘fully ready’ virus without preceding outbreaks of a ‘nearly ready’ virus. So he describes “either the species carrying SARS-CoV-2 is very rare, or extremely few individuals in the species carry SARS-CoV-2, or the carry species is well isolated from human populations”. Combining his claim of dogs as the likely mammalian intestinal host in which viral evolution could take place, with this need for isolation from humans for several years, he targets feral dogs. However this exposes a lack of understanding of dog population dynamics. Dogs are a domesticated species that have evolved alongside people. As a species, they are now entirely useless at sustaining their populations without human support; their mortality is extremely high and their breeding success extremely low. 

The populations of stray dogs that we see across much of the developing world are not feral; these are owned dogs allowed to roam, abandoned owned dogs or community dogs without a single referral household but still benefiting from care provided by people. Importantly, these surviving stray dog populations are not isolated from people, those that do become isolated from human support do not survive for long at all. Hence isolated feral dogs are a poor candidate for an intestinal host in which the ancestor of SARS-CoV-2 could have evolved, simply because these populations do not persist. 

The host that is finally identified as the origin of SARS-CoV-2 is far more likely to be a truly wild animal that can survive and breed for several years isolated from people, before the virus made its zoonotic transmission into people. From that point forwards this became a human disease and that is where our transmission risk lowering policies should focus, with people not dogs or cats.

About International Companion Animal Management (ICAM) Coalition

ICAM supports the development and use of humane and effective companion animal population management worldwide. The coalition was formed in 2006 as a forum for discussion on global dog and cat management issues.

Our key goals are to:

• Share ideas and data
• Discuss issues relevant to population management and welfare
• Agree definitions and hence improve understanding
• Provide guidance as a collegial and cohesive group

Contact information: info@icam-coalition.org

Twitter: @ICAMCoalition