Risk mapping of bovine hypodermosis using geographical information system (GIS) in cattle of subtropical region, Pakistan.

INTRODUCTION: Hypodermosis is an ectoparasitic disease of cattle caused by Hypoderma lineatum and Hypoderma bovis. It is an important health problem of cattle, leading to considerable economic losses. There are various factors that are involved in the spread of this disease such as herd size, location, temperature, humidity, and precipitation. METHODOLOGY: Blood samples from 112 herds were collected to determine the presence of Hypoderma spp. infestation. For these herds, size and location were determined; temperature, humidity, and precipitation data were obtained from meteorological stations; and topographic features were obtained from existing maps and through field work. A regression analysis was then used to generate a risk factor analysis profile for hypodermosis and geographic information system (GIS) was used to map the risks. RESULTS: The GIS map developed showed the degree of infestation in different geographical locations at district and village levels. Cluster analysis demonstrated that hypodermosis prevalence varied within zones and across zones. The regression analysis showed that the temperature in the months of January, February, March, August, and November, and the precipitation in September and October had significant results (p < 0.05) when all the risks factors were analyzed. CONCLUSIONS: It is concluded that different ecological factors have an important impact on the intensity and infestation rate of hypodermosis across the globe. The present study might be used to control and eradicate the hypodermosis across the globe.

Effect of treatment on the dynamics of circulating hypodermin C in cattle naturally infested with Hypoderma lineatum (Diptera: Oestridae).

An antigen capture ELISA, using a murine monoclonal antibody recognising recombinant hypodermin C (rHyC), was used to evaluate the influence of early treatment with eprinomectin (Eprinex) or fenthion (Spotton) on the kinetics of circulating hypodermin C in calves naturally infested with Hypoderma lineatum. No viable larvae were collected from treated animals, whereas a variable number of warbles were found in control animals. Treatment provoked a decrease in circulating HyC levels that was significant 9 days post-treatment (p.t.). Circulating antigen levels in the treated cattle remained detectable for approximately 99 days p.t. In contrast, control animals had no detectable antigen at 64 days p.t., 42 days earlier than in the treated animals. These results suggest that larvae were either gradually killed, resulting in slow release of antigen or they were encapsulated, leading to the slow liberation of antigen. Kinetics of circulating HyC did not differ among the two insecticide treatments. Antibodies persisted, in all groups, throughout the 120-day study. These results suggest that the antigen capture ELISA will be useful as a technique for detecting successful treatment of cattle grub infestations and for the detection of new infestations in previously infested cattle.

Detection of circulating hypodermin C: an antigen capture ELISA for diagnosis of cattle grub (Diptera: Oestridae) infestations.

An antigen capture assay for the detection of circulating hypodermin C was developed for diagnosis of hypodermosis. A murine monoclonal antibody to recombinant hypodermin C was raised using rapid immunization and a one-step hybridization-cloning technique. A highly reactive, specific monoclonal antibody was tested using sera spiked with known quantities of purified, native hypodermin C or with recombinant hypodermin C. Sensitivity of 96.4% and specificity of 95.6% for the antigen capture assay was assessed using a panel of sera from animals unexposed to cattle grubs and from cattle with palpation proven cattle grub infestations. Data from this panel of sera was used to establish the cut-off OD for further testing. The kinetics of circulating hypodermin C was assessed using the assay in three groups of cattle artificially infested with 50, 100 or 200 first instar Hypoderma lineatum. Antigen was first detected approximately 6 weeks after infestation. The amount of antigen detected increased in each group of animals reaching peaks at different times in each group. Levels of antigen fell quickly following arrival of grubs at the back and completion of the molt to second instar.