Suvichai Rojanasthien

Ecologic Risk Factor Investigation of Clusters of Avian Influenza A (H5N1) Virus Infection in Thailand

This study was conducted to investigate space and time clusters of highly pathogenic avian influenza A (H5N1) virus infection and to determine risk factors at the subdistrict level in Thailand. Highly pathogenic avian influenza A (H5N1) was diagnosed in 1890 poultry flocks located in 953 subdistricts during 2004-2007. The ecologic risk for H5N1 virus infection was assessed on the basis of a spatial-based case-control study involving 824 case subdistricts and 3296 control subdistricts from 6 study periods. Risk factors investigated in clustered areas of H5N1 included human and animal demographic characteristics, poultry production systems, and wild birds and their habitats. Six variables remained statistically significant in the final model: flock density of backyard chickens (odds ratio [OR], 0.98), flock density of fighting cocks (OR, 1.02), low and high human density (OR, 0.60), presence of quail flocks (OR, 1.21), free-grazing duck flocks (OR, 2.17), and a poultry slaughterhouse (OR, 1.33). We observed a strong association between subdistricts with H5N1 virus-infected poultry flocks and evidence of prior and concomitant H5N1 infection in wild birds in the same subdistrict.

Investigation of dogs as a reservoir of Penicillium marneffei in northern Thailand

BACKGROUND Penicillium marneffei is a dimorphic pathogenic fungus endemic in Southeast Asia that usually causes disseminated disease, mainly in immunocompromised individuals, especially those with HIV infection. Untreated cases are usually fatal. The only known natural reservoir exists in bamboo rats and there is no firm evidence that these animals are involved in direct transmission to humans. The risk of infection is not restricted to those living in endemic areas; HIV-infected individuals who travel to Southeast Asia have also become infected by P. marneffei. Hence, there must exist sources to which even tourists are exposed on a short-term basis. DESIGN AND METHODS Penicillium is known to infect dogs and this animal is common in the streets and temple areas of Chiang Mai, where there is one of the highest incidences of P. marneffei infection in the world. Dogs have not been well studied as a possible reservoir. To investigate this possibility, we took nasal swabs from 83 outdoor dogs and performed culture and nested polymerase chain reaction (PCR) to detect P. marneffei. RESULTS We found that approximately 13% of nasal swabs from dogs in Chiang Mai, Thailand were positive when tested by two different PCR methods, but culture results were negative. Sequencing the products from both PCR reactions showed 100% identity with P. marneffei, whereas no other known fungi shared both sequences. CONCLUSIONS Our results suggest that dogs might be an animal reservoir for P. marneffei in northern Thailand. This observation should be confirmed by additional studies.

Induction of the ovulatory LH surge in Asian elephants (Elephas maximus): a novel aid in captive breeding management of an endangered species.

A unique feature of the reproductive physiology of Asian elephants (Elephas maximus) is the occurrence of two LH surges before ovulation, instead of one. An anovulatory LH (anLH) surge, the function of which is unknown, occurs consistently 3 weeks before the ovulatory LH (ovLH) surge that induces ovulation. Thus, the ability to induce an ovLH surge would be useful for scheduling natural mating or artificial insemination. The present study tested the efficacy of a gonadotrophin-releasing hormone agonist (GnRH-Ag) to induce LH surges during the follicular phase of the oestrous cycle, which resulted in varied LH responses, but generally none were as high as previously documented natural surges. Thus, for the ovulation-induction trials, nine females were administered 80 microg GnRH-Ag intravenously at three time periods during the oestrous cycle, namely the anovulatory follicular phase, the ovulatory follicular phase and the luteal phase. During the late anovulatory follicular phase, nine of 10 females (90%) responded with an immediate LH surge followed 15-22 days later by an ovLH surge or a post-ovulatory increase in progestagens. In contrast, despite responding to the GnRH-Ag with an immediate increase in LH, none of the females treated during other periods of the oestrous cycle exhibited subsequent ovLH surges. One cow got pregnant from natural mating following the induced ovLH surge. In conclusion, ovLH induction is possible using a GnRH-Ag, but only during a specific time of the anovulatory follicular phase.

Gender, Season and Management Affect Fecal Glucocorticoid Metabolite Concentrations in Captive Goral (Naemorhedus griseus) in Thailand

Chinese goral (Naemorhedus griseus) are a threatened species in Thailand and the focus of captive breeding for possible reintroduction. However, little is known of their biology or what factors in the captive environment affect welfare. Our objective was to determine the impact of gender, season, and management on goral adrenal activity. We hypothesized that differences in fecal glucocorticoid concentrations would be related to animal density. Fecal samples were collected 3 days/week for 1 year from 63 individuals (n = 32 males, 31 females) at two facilities that house the majority of goral in Thailand: Omkoi Wildlife Sanctuary (Omkoi), an off-exhibit breeding center that houses goral in individual pens (16 pens; n = 8 males, 8 females) and in small family groups (8 pens; n = 8 males, 8 females); and the Chiang Mai Night Safari (NS), a zoo that maintains 31 goral (n = 17 males, 14 females) in one large pen. Glucocorticoid metabolite concentrations were higher in male than female goral at Omkoi throughout the year, and there was a seasonal effect on adrenal activity (p<0.05). Goral at Omkoi and NS were used to test the effect of animal density on fecal glucocorticoid excretion of goral housed in similar-sized enclosures. Overall, the highest levels were found at NS (n = 31 adults/pen; 27 m2 per animal) compared to Omkoi (n = 2 adults/pen; 400 m2 per animal) (p<0.05). Overall findings support our hypothesis that animal density and aspects of the captive environment impact adrenal steroid activity in captive goral. In addition, gender and season also had significant effects on glucocorticoid metabolite production. Potential stressors pertaining to the welfare of this species were identified, which will guide future efforts to improve management and create self-sustaining and healthy populations of this threatened species.

Seasonality of fecal androgen and glucocorticoid metabolite excretion in male goral (Naemorhedus griseus) in Thailand.

There is no information on the endocrinology of Chinese goral (Naemorhedus griseus), a high priority species for captive breeding and reintroduction in Thailand. This study characterized fecal androgen and glucocorticoid metabolites in male goral at Omkoi Wildlife Sanctuary to investigate seasonal relationships. Fecal samples were collected 3 days/week for 1 year from eight adult males. Mean androgen metabolite concentrations were greater (P<0.05) during the rainy season (289.82±9.18ng/g) and winter (224.09±11.97ng/g) compared to the summer (195.48±8.23ng/g), and were related to breeding activity. A similar pattern was observed for glucocorticoid concentrations (22.10±0.72ng/g compared to 21.98±0.98ng/g compared to 15.30±0.48ng/g), respectively, and this resulted in a positive correlation between the two hormones (P<0.05). There also were positive correlations between fecal androgen metabolite concentrations and temperature (P<0.05) and day length (P<0.05). In summary, this is the first study to assess endocrine function in male goral, and results showed seasonal variation in testicular and adrenal steroidogenic function, with greater activity in the rainy season and winter. Given that resources for captive male goral are consistent throughout the year, reproduction may be regulated primarily by photoperiod in this species.

Non-invasive endocrine monitoring indicates seasonal variations in gonadal hormone metabolites in dholes (Cuon alpinus)

Abstract Non-invasive hormone monitoring was used to monitor reproductive hormone metabolites in dhole (Cuon alpunus) faecal samples. The findings indicate that dholes are seasonal breeders. However, the geographical origin of the animals may influence the onset of the breeding season. Finally, the study demonstrated evidence of polyoestrus in the female.

An integrative approach to enhancing small-scale poultry slaughterhouses by addressing regulations and food safety in northern -Thailand

BackgroundIn Asian countries, small-scale rural poultry meat production can face challenges due to food safety policies that limit economic growth and hinder improvement of sanitation and disease prevention. In this study, an integrative, participatory research approach was used to elucidate the sanitation and disease prevention practices in small-scale poultry slaughterhouses in rural northern Thailand.MethodsInitial steps included the identification of key stakeholders associated with the meat production chain, development of a research framework, and design of a methodology based on stakeholder consultations. The framework and methodology combine issues in five major areas: (1) public health, (2) socioeconomics, (3) policy, (4) veterinary medicine, and (5) communities and the environment. Methods used include questionnaires, direct observation, focus groups, and in-depth interviews. In addition, a microbiological risk assessment approach was employed to detect Salmonella contamination in meat processing facilities. The microbial risk assessment was combined with stakeholder perceptions to provide an overview of the existing situation, as well as to identify opportunities for upgrading slaughterhouses in order to more effectively address matters of food safety, processing, and government licensing.ResultsThe conceptual framework developed elucidated the complex factors limiting small-scale slaughterhouse improvement including a lack of appropriate enabling policies and an apparent absence of feasible interventions for improvement. Unhygienic slaughterhouse management was reflected in the incidence of Salmonella contamination in both the meat and the surrounding environment.ConclusionThere is potential for the use of an integrative approach to address critical problems at the interface of rural development and public health. The findings of this study could serve as a model for transdisciplinary studies and interventions related to other similar complex challenges.

Intranasal immunization with a recombinant outer membrane protein H based Haemorrhagic septicemia vaccine in dairy calves

Haemorrhagic septicemia (HS) is a contagious disease in cattle with high morbidity and mortality rates. HS vaccine in Thailand is an oil-adjuvant formulation, and is difficult to administer. The present study aimed to formulate and evaluate the protection in dairy calves conferred by immunization with an in-house intranasal HS vaccine. The intranasal vaccine was formulated in a total volume of 500 µl containing either 50 or 100 µg of the recombinant outer membrane protein H (rOmpH) of Pasteurella multocida strain M-1404 (serovar B:2), and 10 µg of Cytosine-phosphate-guanosine oligodeoxynucleotides (CpG-ODN) as a mucosal adjuvant. Intranasal immunizations were conducted three times at three-week intervals. The antibodies post-immunization were detected by indirect ELISA and demonstrated efficient in vitro activity in suppressing a P. multocida strain from the complement-mediated killing assay. An intranasal vaccine induced both the serum IgG and secretory IgA levels that were significantly higher than the level conferred by the parenteral vaccine (P<0.05). Challenge exposure was conducted with a P. multocida strain M-1404 at day 72 of the experiments. The immunized calves had reduced clinical signs after challenge exposure that would normally result in disease proliferation. We conclude that intranasal vaccination of calves with rOmpH with CpG-ODN 2007 stimulated serum and secretory antibodies to rOmpH and whole cells of P. multocida strain M-1404 antigen. Moreover, it would result in protection in calves against artificial P. multocida infection.