H5N1 in cats and civets

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ANIMAL HEALTH SPECIAL REPORT H5N1 in cats

Introduction

At the end of February 2006 highly pathogenic avian influenza (HPAI),

caused by the H5N1 virus was detected in a domestic cat found dead on

the northern island of Ruegen, Germany. Since mid-February, over 100

birds have died on this island and tests confirmed H5N1 infection.

Also in Asia, cats and other felidae are occasionally found to be

infected with H5N1 since the start of the poultry epidemic end 2003.

Experimental studies have shown that the domestic cat can become

infected with the virus and that cat to cat transmission is possible

in principle. Serological studies in several Asian countries suggest

that dogs may also contract the H5N1 infection. Countries in Europe

have advised owners of pets living near H5N1 wild bird foci to keep

cats indoors and dogs on a leash when taken for a walk.

These recent events lead to many questions by the public and pet

owners to which the veterinary profession has to respond. In

addition, there may be exposure of pet owners and veterinarians. For

example, when animals infected with H5N1 (eg birds, dogs and cats)

are brought to the veterinary clinic. Important are also the

contribution veterinary practitioners can make in the surveillance of

the disease for the presence of the H5N1 infection.

This section provides information for the general public and

professionals about the risk of cats contracting H5N1 virus and the

role of cats in the spread of avian influenza H5N1.

During a H5N1 outbreak in poultry in 1997 in Hong Kong, the first

clinical human cases of this sub-type were reported with several

fatalities. From the end of 2003 to date (March 2006) 173 people have

been confirmed infected with the H5N1 virus of which 93 have died.

Except for 1 case, human-to-human transmission has probably not

occurred. Although H5N1 is relatively common to wild birds and

poultry, humans and other mammals are also at risk of HPAI infection.

Highly pathogenic avian influenza in poultry is of growing concern

due to the current geographic extent comprising Asia, Africa and

Europe showing potential for pandemic spread. The virus is highly

contagious and already over 200 million domestic birds have either

been culled or died of the disease. Table 1 shows the timeline for

avian influenza in cats and other felidae.

Timeline of (H5N1) avian influenza in cats and other felidae (and

civets)

1970s & 1980s

Research revealed that infection of domestic cats with influenza A

subtypes H3N2 from humans, H7N3 from a turkey, and H7N7 from a harbor

seal (Phoc vitulina) produces transient virus excretion and a

temporary increase in body temperature but did not induce any other

clinical signs of disease.

December 2003

Two leopards and two tigers died at a zoo in Thailand after feeding

on chicken carcasses. Investigation confirmed H5N1 in tissue samples

from all 4 animals. This was the first report of influenza causing

disease and death in big cats.

September 2004

Research shows that domestic cats experimentally infected with H5N1

develop severe disease and can spread infection to other cats.

October 2004

A H5N1 outbreak in zoo tigers in Thailand reportedly fed on chicken

carcasses. Eventually, 147 out of the population of 441 tigers died

or had to euthanized for animal welfare reasons.

June 2005

Tests on three civets that died late June 2005 in Viet Nam revealed

H5N1, marking the first infection of this species with the virus.

These endangered Owston's palm civets were raised in captivity;

source of infection is still unknown.

October 05 February 06

FAO field veterinarians report unusual high cat mortality in Iraq

and Indonesia in the vicinity of H5N1 outbreaks in poultry.

28 February 2006

H5N1 confirmed in a cat on the Baltic Sea island of Ruegen

(Germany). Over 100 wild birds had been found dead on the island

during previous weeks.

General Information

Role of cats in virus transmission Research has shown that domestic

cats may die from H5N1 virus. Also horizontal transmission has been

proven. However, it is unlikely that cats play a role in the natural

transmission cycle of H5N1 viruses. Cat infections occasionally occur

in association with H5N1 outbreaks in domestic or wild birds, e.g.

when cats feed on infected birds. Experimental/infected cats shed the

virus via the respiratory and intestinal tract, and may therefore

transmit the virus to other cats. Naturally infected cats are thus in

theory, able to spread the virus

In areas where H5N1 Infected wild birds are reported it can not be

excluded that cats become infected. Although most wild birds infected

are waterfowl, not normally the species cats interact with, H5N1 is

potentially infectious to numerous other bird species and it can not

be ruled out that passerines or pigeons which do interact with cats

get infected

In areas where poultry is infected with H5N1 there is a risk that

cats become infected with H5N1 through contact with infected poultry

or their faeces. Anecdotal reports support the notion that contact

with infected poultry (faeces and eating infected carcasses) forms a

source of infection for cats. Cats probably have little or no

contribution to the spread of the disease because the number of

infected poultry is much higher than the number of infected cats;

poultry shed much more virus than cats. Nevertheless, cats may play a

role in the spread of the virus to other animals. Report to the local

veterinary authority any evidence of significant animal mortality

both wild and domestic.

Theoretically there is a possibility that cats transmit infection to

humans. However, given the risk that cats become infected with HPAI

is low, the risk to human infection is therefore limited.

The role of stray cats

Due to their greater mobility, stray cats could spread the disease

into new areas. If infected, stray cats may become a source of

contamination to poultry and mammals, including humans.

The role of other mammals

The ability of catching the H5N1 virus is not restricted to cats.

Reports show infection in tigers, leopards and civets. Also dogs and

pigs may become infected with the virus. Given the broad host

spectrum of the H5N1virus, the possibility that also other wild or

domesticated mammals including seals, mustelidae or furbearing

animals, become infected by contacting infected animals is present.

All carnivores could become infected through eating infected poultry

or infected wild birds.

Recommendations

Areas where H5N1 HPAI has been diagnosed or is suspected in poultry

or wild birds:

Report to the local veterinary authority any evidence of significant

bird mortality both wild and domestic

Be especially vigilant for any dead or sick cats and report such

findings to the local vet

Make sure contact between cats and wild birds or poultry (or their

faeces) is avoided and/or keep cats inside

If cats bring a sick or dead bird inside the house, put on plastic

gloves and dispense of the bird in plastic bags for collection by

local veterinary animal handlers

Keep stray cats outside the house and avoid contact wit them

If cats show breathing problems or nasal discharge, a veterinarian

should be consulted

Do not touch or handle any sick-looking or dead cat (or other animal)

and report to the authorities

Wash hands with water and soap regularly and especially after

handling animals and cleaning their litter boxes or coming in contact

with faeces or saliva

Dogs can only be taken outside the premises if kept restraint

Do not feed any water birds

Disinfect (e.g. with bleach 2-3 %) cages or other hardware with which

sick animals have been transported or been in contact with.

Wash animal blankets with soap or any other commercial detergent

Information for veterinarians

Avian influenza in other animal species

Hosts: Wildbird hosts for H5N1 in order of importance are probably

Anatidae (ducks, geese, swans), Charadriiform (gulls and shorebirds)

and Passeriform (sparrows and starling). Lately swans have been found

infected with H5N1 in a number of European countries (e.g. Austria,

Germany, France and Romania, etc.). In poultry, both aquatic and

terrestrial species become infected but the virus is particularly

aggressive in chicken.

Carnivores: can become infected, after consuming infected poultry

that succumbed to the disease. To date no H5N1 clinical cases of dogs

have been reported but in an unpublished study carried out in 2005 by

the National Institute of Animal Health in Bangkok, researchers

tested 629 village dogs and 111 cats in the Suphan Buri district of

central Thailand. Out of these, 160 dogs and 8 cats had antibodies to

H5N1, indicating that they were infected with the virus or had been

infected in the past. An eqiune virus has recently shown up in dogs.

This inter-species re-assortment is not uncommon for type A influenza

viruses.

Pigs are known " „mixing vessels " for different influenza virus

subtypes and therefore present a risk for avian influenza virus re-

asserting with a human influenza virus into a strain more apt to

infect humans. Regarding the present H5N1 subtype, studies conducted

in pigs in Vietnam yielded 8 animals out of the 3000 investigated

pigs seropositive. None of the animals had any clinical signs and it

was not possible to isolate any virus

Ruminants appear at lower risk. So far no cattle have been identified

as carrying any influenza type A virus. Horses are susceptible to

Influenza viruses but so far mainly H3N8 have been identified.

Regular vaccination is carried out. Experimentally mice can be

infected but their role in natural transmission has not been

established.

Public health implications

Humans and other mammals need to come in contact with large amounts

of virus to become infected. In case of an infection with H5N1,

mammals and humans apparently only shed small amounts of virus,

contributing to reduced risk of spread among themselves. Recent data

from experimentally infected cats' evidenced extra-respiratory

replication of the H5N1 and excretion of virus in faeces of cats need

to be taken into consideration. Hygienic practices need to be re-

enforced, frequent washing of hands with water and soap especially

after handling animals, cleaning cat litter boxes as well as before

and after the preparation of food.

Occupational health and safety

Veterinarians and their staff are specifically at risk of coming into

contact with infected cats, in case the disease becomes more

widespread among this species. Normally, veterinarians and their

staff engage in frequent hand washing and disinfect examination

tables and instruments to reduce the general risk of disease

transmission among their patients and to protect the persons present

in the consultation room from eventual exposure.

Advice for veterinarians

The following is advised for veterinarians:

Advice to pet owners

Be ware of possibility to receive (sick) cats infected with H5N1

Take hygienic measures when handling sick cats (gloves and surgical

masks)

Take deep oro-pharyngeal swabs of suspected animals (e.g. animals

with respiratory problems) and sent them to the laboratory clearly

indicating the type of examination requested Support cases to be

reported to veterinary authorities

Inform owners of suspected animals and provide them with clear and

practical information, avoiding creating any panic among cat owners

or the general public.

Provide veterinarians are advised to contact the Veterinary

Authorities in their respective countries for specific instructions

http://www.fao.org/ag/againfo/subjects/en/health/diseases-

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