Updates on avian flu infecting Zoo animals in Asia

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AVIAN INFLUENZA, EASTERN ASIA (129): - THAILAND, TIGERS, OIE

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A ProMED-mail post

<http://www.promedmail.org>

22 Oct, 2004

ProMED-mail<promed

Source: OIE Disease Information 22 Oct 2004 Vol. 17 - No. 43 [edited]

<http://www.oie.int/eng/info/hebdo/AIS_22.HTM#Sec4>

 

 

Highly Pathogenic Avian Influenza in Thailand in felines in a zoo

 

Emergency report

 

Information received on 19 and 20 Oct 2004 from Dr Yukol Limlamthong, General, Department of Livestock Development (DLD), Ministry of

 

Agriculture and Cooperatives, Bangkok:

 

Date of the report: 20 Oct 2004.

Nature of diagnosis: clinical and laboratory.

Date of initial detection of animal health incident: 11 Oct 2004.

Estimated date of primary infection: 8 Oct 2004.

Date of confirmation of diagnosis: 18 Oct 2004.

 

Outbreak:

Location

Chon Buri province, Si Racha district

No. of outbreaks: 1 (a zoo)

 

Description of affected population: tigers (_Panthera tigris_) in

captivity.

The sick and dead tigers are aged between 8 months and 2 years.

 

Total number of animals in the outbreak:

 

species / fau / avi*

susceptible / 441 / 12

cases / 55 / 0

deaths / 30 / 0

destroyed / .. / ..

slaughtered / ... / ...

 

* 10 peacocks and 2 ostriches kept in a separate area of the zoo

 

Diagnosis: the clinical manifestations began on 11 Oct 2004 with

weakness,

lethargy, respiratory distress and high fever (about 41-42 degrees

Celsius). There was no response to any antibiotic treatment. Death

occurred

within 3 days following the onset of clinical signs with severe

pulmonary

lesions.

 

A. Laboratories where diagnosis was made: National Institute of Animal

Health and Laboratories of the Veterinary Faculties of Kasetsart and

Chulalongkorn Universities.

 

B. Diagnostic tests used:

- real-time PCR(1) (18 Oct 2004): positive;

- virus isolation by egg inoculation (19 Oct 2004): positive.

 

C. Causal agent: highly pathogenic avian influenza virus type A (H5).

 

Epidemiology:

 

A. Source of agent / origin of infection: chicken carcass feeding

appears

to be the probable cause of infection. The tigers in this zoo have been

fed

with chicken carcasses for many years. A single feed supplier is

responsible for provision of tiger feed for the affected zoo.

Preliminary

investigations revealed that the feeding stuffs consisted not only of

fresh

chicken carcasses from a local slaughterhouse but also whole chickens

from

other sources in the area. The whole chickens are the potential cause of

 

the infection. The DLD investigation team is endeavouring to trace the

source of these chickens.

 

B. Mode of spread: at present, the preliminarily conclusion is that the

disease is attributable to a common source of infection by chicken

feeding

rather than animal-to-animal transmission.

 

C. Other epidemiological details: there are 10 peacocks and 2 ostriches

in

a separate area of the zoo. These birds' health is still normal. They

will

be used as sentinel animals for both clinical and serological

monitoring.

 

Control measures:

- the zoo has been in quarantine since 19 Oct 2004;

- veterinary officials have conducted 5-km radius movement management

and

surveillance;

- well-cooked chicken carcasses or pork and beef are recommended for

feeding the tigers for the time being;

 

Vaccination remains prohibited.

 

(1) PCR: polymerase chain reaction

 

--

ProMED-mail

<promed

 

[The crude attack rate for avian influenza in these zoo tigers is 12.5

percent, but this may be a minimum estimate, as the report does not

indicate whether all tigers in the zoo were fed contaminated feed.

Indeed,

it may be impossible to know except in the unlikely situation in which

the

feed source is still available and excellent records were kept.

 

The case fatality rate of 55 percent indicates either some combination

of

high doses of virus, highly susceptible tigers and/or a particularly

virulent H5N1 strain. This is a valuable opportunity to learn how this

virus acts in a new species, so no stone should be left unturned. What

we

learn may be very useful should we have to contend with the jump from

chickens to humans, especially if there is a foodborne vehicle involved.

I

hope epidemiologists will put great effort into working up this

outbreak.-

Mod PC]

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Thu 21 Oct 2004

Henry L Niman, PhD <henry_niman

Source: The Nation, Fri 22 Oct 2004 [edited]

<http://www.nationmultimedia.com/2004/10/22/national/index.php?news=nati

onal_15147937.html>

 

 

Thailand: Up to 100 Tigers in Sri Racha Zoo Now Affected by Avian

Influenza

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Up to 100 tigers may need to be culled to stop the bird-flu outbreak at

Sri

Racha Tiger Zoo, Preecha Ratanaporn, a Director at the National Park,

Wildlife and Plant Conservation Department, said yesterday. Over 70

tigers

at the private zoo have succumbed to avian influenza, including 30 put

down

on Wednesday to prevent the virus from spreading.

 

Lab tests yesterday showed the avian influenza virus that killed the big

 

cats at Sri Racha Zoo had not mutated, said Dr Charal Trinvuthipong, of the government's bird-flu centre. But the virus that killed

 

the tigers [caused severe disease], and prompted an order from Charal

for

it to be " decoded " to determine if it was the same H5N1 type already

found

across the country or a new strain.

 

A further 25 tigers at the zoo suspected to be infected have been put

under

surveillance, while 350 others that appear healthy and strong will also

be

monitored. The tigers are being given medicine to prevent them catching

the

virus, veterinarian Somchuan Ratanamangkalanont said. " This medicine is

the

tablets that are given to humans to fight bird flu . We hope they can

control the spread of the virus at the zoo, " he said. Tigers that look

ill

will be immediately destroyed. " Tigers are prone get infections easily

and

we need to watch them closely, " he said.

 

Charal rejected reports that crocodiles at the Samut Prakan Crocodile

Farm

and Zoo had perished from avian influenza, saying reptiles were not

susceptible to the avian virus. Only mammals such as dogs [?] and cats

could be affected, he said. Dr Thawat Suntrajarn, Director-general of

the

Disease Control Department, also ruled out the possibility that the

Samut

Prakan crocodiles had died from the virus. " The farm owner said

crocodile

deaths are a normal phenomenon and they usually die every year, " he

said.

 

Thawat said the sick tigers at Sri Racha would be put down with lethal

injections that caused no pain. The 57 zookeepers who looked after the

animals have been asked to stay at home and visit the hospital daily for

 

physical check-ups. Aviaries in Songkhla have also been ordered to close

 

temporarily and are strictly banned from moving birds in and out, said

Chalerm-wut Kasetsomboon, Director of the Songkhla Zoological Office.

The

aviaries are also prohibited from buying bird feed containing poultry.

Their workers have been told to watch their health. " Bird sanctuary

officials must fully cover their bodies to prevent infection, and they

are

not allowed to touch bird droppings, " Chalermwut said.

 

--

Henry L Niman, PhD

<henry_niman

 

[The details of this incident are still rather confused. It is stated

that

the virus has not " mutated " , although it has still to be " decoded " .

Presumably the treatment prescribed to protect healthy animals is

administration of the oral neuraminidase inhibitor oseltamivir. It

appears

that the infection may be spreading now by the respiratory route, as the

 

supply of chicken carcasses has ceased. A fuller account is awaited.

 

ProMED-mail has received the following relevant information from Dr.

Yang

Li <yangli of F.I.C. (<http://www.flu.org.cn>). " A paper

published in China Journal of Veterinary Science in 2003 reported that

tigers died of influenza virus infection in 2002. The sequence of the NP

 

protein gene indicated an influenza A virus infection. Though the

subtype

of the influenza A virus is not mentioned in the paper, phylogenetic

analysis showed great similarity between the NP gene of

A/Tiger/Harbin/2/2002 and A/duck anyang/AVL/1/2001(H5N1) and

A/goose/Guangdong/1/96(H5N1).

 

Further details can be found by following the link

<http://www.flu.org.cn/news/200410228729.htm> " - Mod.CP]