West Nile virus and its emergence in the United States of America

Zoonotic West Nile virus (WNV) circulates in natural transmission cycles involving certain mosquitoes and birds, horses, humans, and a range of other vertebrates are incidental hosts. Clinical infections in humans can range in severity from uncomplicated WNV fever to fatal meningoencephalitis. Since its introduction to the Western Hemisphere in 1999, WNV had spread across North America, Central and South America and the Caribbean, although the vast majority of severe human cases have occurred in the United States of America (USA) and Canada. By 2002-2003, the WNV outbreaks have involved thousands of patients causing severe neurologic disease (meningoencephalitis and poliomyelitis-like syndrome) and hundreds of associated fatalities in USA. The purpose of this review is to present recent information on the epidemiology and pathogenicity of WNV since its emergence in North America.     

‘Candidatus Liberibacter solanacearum’ detected in Trioza urticae using suction trap-based monitoring of psyllids in Germany

Journal of Plant Diseases and Protection - Psyllids are small, phloem-feeding insects. Several species are vectors of economically important pathogens, such as ‘Candidatus Liberibacter...     

Validation of 2 commercial Neospora caninum antibody enzyme linked immunosorbent assays

This is a validation study of 2 commercially available enzyme linked immunosorbent assays (ELISA) for the detection of antibodies against Neospora caninum in bovine serum. The results of the reference sera (n = 30) and field sera from an infected beef herd (n = 150) were tested by both ELISAs and the results were compared statistically. When the immunoblotting results of the reference bovine sera were compared to the ELISA results, the same identity score (96.67%) and kappa values (K) (0.93) were obtained for both ELISAs. The sensitivity and specificity values for the IDEXX test were 100% and 93.33% respectively. For the Biovet test 93.33% and 100% were obtained. The corresponding positive (PV+) and negative predictive (PV−) values for the 2 assays were 93.75% and 100% (IDEXX), and 100% and 93.75% (Biovet). In the 2nd study, competitive inhibition ELISA (c-ELISA) results on bovine sera from an infected herd were compared to the 2 sets of ELISA results. The identity scores of the 2 ELISAs were 98% (IDEXX) and 97.33% (Biovet). The K values calculated were 0.96 (IDEXX) and 0.95 (Biovet). For the IDEXX test the sensitivity and specificity were 97.56% and 98.53%, whereas for the Biovet assay 95.12% and 100% were recorded, respectively. The corresponding PV+ and PV− values were 98.77% and 97.1% (IDEXX), and 100% and 94.44% (Biovet). Our validation results showed that the 2 ELISAs worked equally well and there was no statistically significant difference between the performance of the 2 tests. Both tests showed high reproducibility, repeatability and substantial agreement with results from 2 other laboratories. A quality assurance based on the requirement of the ISO/IEC 17025 standards has been adopted throughout this project for test validation procedures.     

Intestinal cryptosporidiosis and reovirus isolation from bobwhite quail (Colinus virginianus) with enteritis

An acute enteric disease of young pen-raised bobwhite quails was studied. Affected quails had white, watery diarrhea accompanied by dehydration and subsequent death. Mortality from hatch to 17 days of age ranged from 30 to 45% in the three flocks examined. Small intestines were thin-walled and distended with fluid and gas. Microscopic lesions in the intestinal tract consisted of villus atrophy, villus fusion, and sloughing of cells at the tip of the villi in duodenum, jejunum, and ileum. Cryptosporidium sp. and reovirus were identified in affected quails.     

Experimental Infection of Lymnaea palustris snails with Fascioloides magna

This report describes experimental infection of Lymnaea (Galba) palustris. (Müller, 1774) snails with Fascioloides magna (Bassi, 1875). Of 725 L. palustris, 400 survived the experimental infection and in 172 (43%) the developmental cycle of the fluke was completed. Free emergence of cercariae was obtained was obtained 68 days after infection. The infectivity of metacercariae thus obtained was demonstrated in guinea-pigs, rabbits and a Cameroon goat. In sheep, the infection produced only changes in the organs, but no flukes could be recovered. Considering that L. palustris are found frequently in natural habitats in Czechoslovakia, they should be considered as possible intermediate hosts for F. magna.