Seroprevalence and phylogenetic analysis of Toxoplasma gondii from domestic cats, captive wild felids, free-range wild felids and rats in certain regions of Thailand

Toxoplasmosis is an important zoonotic disease caused by Toxoplasma gondii, an obligated zoonotic apicomplexan parasite. The infection varies according to geographical areas. This work aimed to study the seroprevalence and genotype of T. gondii infection in domestic, captive and free-range wild felids, and in their small mammal prey, rats (Rattus spp). Two hundred and ninety three sera, received from the 4 individual animal groups in Thailand, were tested using the indirect latex agglutination test (ILAT) for specific antibody detection. The nested-PCR for glycerol-3-phosphate (B1) and bradyzoite surface antigen (SAG4) gene detection was used to detect seropositive animals and PCR product was submitted for DNA sequencing. Out of the 293 sera, ILAT showed 11.68% positive results. T. gondii were found 3.48% seropositive in the domestic cats (n=86), 18.84% seropositive in the captive wild felids (n=138), 14.28% seropositive in the free-range wild felids (n=7), and 6.67% seropositive in the murine prey (n=60). Tissues from the seropositive animals such as liver, heart, brain and skeletal muscle were collected, and then DNA was extracted to perform nested-PCR and sequence analysis. By the nested-PCR, the brain and muscle tissues received from 3 black rats and a clouded leopard (1.37%) were found positive for T. gondii. SAG4 and B1 might serve as novel genetic markers for population genetic studies of T. gondii isolates. Based on the ML phylogenetic tree analysis of SAG4 and B1 coding sequences, T. gondii found in 3 murine prey and a clouded leopard was close to T. gondii RH type I strain with approximately 99-100% similarity. This is the first report on the relation of T. gondii infection with strain identification in domestic cats, captive and free-range felids, and murine in Thailand. Better understanding of the genetic diversity will lead to better management, prevention and treatment of this disease in the valuable species of wild felids

A study of risk factors for infection with HPAI H5N1 in small poultry farms in Thailand using a questionnaire survey

A questionnaire was used to collect data on small poultry farm management and wild bird observed in poultry keeping areas to identify putative risk factors for infection with HPAI H5N1. The study was conducted in 2008 in four subdistricts of central Thailand that had experienced outbreaks of HPAI H5N1 in poultry. Descriptive and inferential analyses including univariable analyses and multivariable logistic regression were used to identify putative risk factors. Risk factors included purchasing native chickens/fighting cocks from commercial hatcheries, replacing or restocking birds individually, and observing lesser whistling ducks (Dendrocygna javanica) on the farm daily. Selecting healthy animals when purchasing animals to ensure that they were disease free was a protective factor. To fully understand the epidemiology of infection of small poultry farms with HPAI H5N1, control of movement of domestic poultry and serological and virological testing of the poultry population should be applied

Virological and molecular epidemiological investigations into the role of wild birds in the epidemiology of influenza A/H5N1 in central Thailand

A serological and virological surveillance program to investigate the HPAI H5N1 virus in wild bird populations was undertaken from February 2007 to October 2008. The purpose of the survey was to investigate the infection status in free ranging wild birds in Banglane district, Nakhon Pathom province, central Thailand. Samples from wild birds were collected every two months. Choanal and cloacal swabs, serum and tissue samples were collected from 421 birds comprising 44 species. Sero-prevalence of the virus tested by H5N1 serum neutralization test (using a H5N1 virus clade 1; A/chicken/Thailand/vsmu-3-BKK/2004) was 2.1% (8 out of 385 samples; 95% CI 0.7, 3.5). Species that were antibody positive included rock pigeons (Columba livia), Asian pied starling (Gracupica contra), spotted dove (Streptopelia chinensis), oriental magpie robin (Copsychus saularis), blue-tailed bee-eater (Merops philippinus), myna (Acridotheres spp.), and pond heron (Ardeola spp.). Prevalence by H5N1 virus isolation was 0.5% (2 out of 421 samples; 95% CI 0.0, 1.1); the two H5N1 virus-positive samples were from Asian pied starling (Gracupica contra) and white vented myna (Acridotheres grandis). Positive virological samples were collected in June 2007 while all positive serology samples were collected between May and August except for one sample collected in December 2007. No positive samples were collected in 2008. Molecular studies revealed that the wild bird H5N1 viruses were closely related to poultry viruses isolated in other parts of Thailand. However, there was no poultry H5N1 prevalence study performed in the study site during the time of this wild bird survey. Interpretation of source of virus isolates would include spill-over of H5N1 viruses from contaminated sources due to movement of domestic poultry and/or fomites from other areas; or infection of wild birds within the outbreak locations and then translocation by wild bird movement and interaction with wild birds inhabiting distant locations