Epidemiology and genotypes of group A rotaviruses in cattle and goats of Bangladesh, 2009-2010.

Group A rotavirus (RVA) is recognized as a major cause of severe gastroenteritis in newborn calves and goat kids. We estimated the proportion of ruminants infected with rotavirus and identified the circulating genotypes in cattle and goats in Bangladesh. Between May 2009 and August 2010, fecal samples were collected from 520 cattle and goats presenting with diarrhea at three government veterinary hospitals in three districts of Bangladesh. All samples were screened for RVA RNA using real-time, one-step, reverse transcription polymerase chain reaction (qRT-PCR). Of the 520 animals tested, 11.7% (61) were positive for RVA RNA, with 6.2% (15/241) and 16.5% (46/279) positivity in cattle and goats, respectively. RVA positive samples were further characterized by nucleotide sequence analysis of two structural protein gene fragments, VP7 (G genotype), and VP4 (P genotype). Among 17 successfully sequenced strains, G8 (17.9%) was the most prevalent G-genotype followed by G10 (8%) and G6 (1.6%). P[1] (11.3%) was the most frequently detected P-genotype followed by P[11] (3.2%) and P[15] (1.6%). The most common VP7/VP4 combinations for cattle were G10P[11], G10P[15], and G6P[11], and for goat, G8P[1], and G10P[1]. Phylogenetic analysis of the RVA strains showed clustering with bovine and caprine strains from neighboring India. The study adds to our understanding of the genetic diversity of bovine and caprine rotavirus strains in Bangladesh. Our findings highlight the importance of rotavirus surveillance in cattle and goat populations, which may serve as a potential source for genetic reassortment and zoonotic transmission.

Epidemiology and genetic characterization of Peste des petits ruminants virus in Bangladesh.

Peste des petits ruminants (PPR) is an acute, highly contagious disease responsible for high morbidity and mortality rates in susceptible sheep and goats. Adequate knowledge of the diversity of circulating strains of PPR virus will help livestock authorities choose appropriate vaccines. The objective of this study was to describe the epidemiology of PPR and characterize the strains circulating in Bangladesh. Veterinarians enrolled goats showing signs consistent with PPR, including diarrhoea, fever and respiratory distress, from three veterinary hospitals. Post-treatment follow up was carried out to ascertain health outcomes of the goats. Faecal and throat swab samples were collected from the goats and tested for PPRV RNA using real-time reverse transcription polymerase chain reaction (rRT-PCR). Nucleotide sequence-based phylogenetic analyses of two structural genes, the nucleocapsid (N gene), and the haemagglutinin (H gene) were studied to determine the genetic variations of PPRV strains. Of the 539 goats enrolled, 38% (203/539) had detectable RNA for PPRV. We were able to follow up with 91% (184/203) of the PPRV infected goats; 44 of them died (24%). PPRV was more frequently identified in the summer (45%) than in the rainy season (29%) (Odds ratio = 1.9, 95% confidence interval: 1.3-3.1). Bangladeshi strains were phylogenetically similar to the lineage IV PPRV strains; showing particularly strong affiliation with Tibetan and Indian strains. PPR is a common viral infection of the goats in Bangladesh, with a high case-fatality rate. This study confirms the circulation of lineage IV PPRV in the country with unique amino acid substitutions in N and H proteins and provides baseline data for vaccine development and implementation.

Risk factors and clusters of Highly Pathogenic Avian Influenza H5N1 outbreaks in Bangladesh.

Between March 2007 and July 2009, 325 Highly Pathogenic Avian Influenza (HPAI, subtype H5N1) outbreaks in poultry were reported in 154 out of a total of 486 sub-districts in Bangladesh. This study analyzed the temporal and spatial patterns of HPAI H5N1 outbreaks and quantified the relationship between several spatial risk factors and HPAI outbreaks in sub-districts in Bangladesh. We assessed spatial autocorrelation and spatial dependence, and identified clustering sub-districts with disease statistically similar to or dissimilar from their neighbors. Three significant risk factors associated to HPAI H5N1 virus outbreaks were identified; the quadratic log-transformation of human population density [humans per square kilometer, P=0.01, OR 1.15 (95% CI: 1.03-1.28)], the log-transformation of the total commercial poultry population [number of commercial poultry per sub-district, P<0.002, OR 1.40 (95% CI: 1.12-1.74)], and the number of roads per sub-district [P=0.02, OR 1.07 (95% CI: 1.01-1.14)]. The distinct clusters of HPAI outbreaks and risk factors identified could assist the Government of Bangladesh to target surveillance and to concentrate response efforts in areas where disease is likely to occur. Concentrating response efforts may help to combat HPAI more effectively, reducing the environmental viral load and so reducing the number of disease incidents.