Poultry as a Host for the Zoonotic Pathogen, Campylobacter jejuni

6 march 2012

According to researchers in Belgium, the number of human campylobacteriosis cases associated with chickens remains high because, although it is known that chickens are the number one risk factor for disease in humans, there are no effective strategies to reduce Campylobacter prevalence in flocks.

Campylobacteriosis is the most reported foodborne gastroenteritic disease and poses a serious health burden in industrialised countries, according to David Hermans of Ghent University and co-authors there and at the Institute for Agricultural and Fisheries Research in Melle, both in Belgium.

In their paper in Vector-Borne and Zoonotic Diseases, they continue that disease in humans is mainly caused by the zoonotic pathogen, Campylobacter jejuni. Due to its wide-spread occurrence in the environment, the epidemiology of Campylobacter remains poorly understood. It is generally accepted, however, that chickens are a natural host forC. jejuni, and for Campylobacter spp. in general, and that colonised broiler chicks are the primary vector for transmitting this pathogen to humans. 
Several potential sources and vectors for transmitting C. jejuni to broiler flocks have been identified. Initially, one or a few broilers can become colonised at any time between two weeks of age and the end of rearing, after which the infection will rapidly spread throughout the entire flock. Such a flock is generally colonised until slaughter and infected birds carry a very high C. jejuni load in their gastrointestinal tract, especially the caeca. 

This eventually results in contaminated carcasses during processing, which can transmit this pathogen to humans, say the researchers. Recent genetic typing studies showed that chicken isolates can frequently be linked to human clinical cases of Campylobacter enteritis. However, despite the increasing evidence that the chicken reservoir is the number one risk factor for disease in humans, no effective strategy exists to reduce Campylobacter prevalence in poultry flocks, which can in part be explained by the incomplete understanding of the epidemiology of C. jejuni in broiler flocks. 

Hermans and co-authors conclude that the number of human campylobacteriosis cases associated with the chicken vector remains strikingly high

Hong Kong Reports More HPAI in Wild Birds

HONG KONG - The country's veterinary authorities have reported three new outbreaks of highly pathogenic avian influenza in Cheung Chau and Mongkok.

Two dead oriental magpie robins were collected on 25 and 27 February and a crested goshawk was collected on 24 February.

An intensive surveillance system is in place for all poultry farms, poultry markets and pet bird shops in Hong Kong. The H5N1 infected wild birds and goose carcass from unknown source were detected in ongoing surveillance programme on wild birds. The dates of the outbreaks are the same as the dates the birds were collected (i.e. 17 December 2011, 30 December 2011, 1 January 2012, 12 January 2012, 20 January 2012 , 30 January 2012 , 6 February 2012, 7 February 2012, 8 February 2012, 24 February 2012, 25 February 2012 and 27 February 2012 respectively).

A total of 19,451 poultry, including 15,569 chickens, 810 pigeons, 1,950 pheasants and 1,122 silky fowls were culled in the Cheung Sha Wan Temporary Wholesale Poultry Market on 21 December 2011. The Wholesale Poultry Market was closed. Importation of live poultry and movement of poultry in local farms is banned for 21 days.

Surveillance and monitoring of local chicken farms has been stepped up. No H5 virus was detected in samples taken from the 30 chicken farms in Hong Kong. The Wholesale Poultry Market was reopened on 12 January 2012. 

Antimicrobial Resistance part 3

The 

 main antimicrobial families, their mode of action and common resistance mechanisms are summarised in Table 1.