DEVELOPMENT OF ELISA BIOASSAY AND RISK MAPPING OF BOVINE HYPODERMOSIS IN NORTHERN PUNJAB, PAKISTAN

Abstract

Hypodermosis is an ectoparasitic disease of cattle caused by Hypoderma bovis and H lineatum. It is an important health issue in animals leading to substantial economic loss. In live animals, the diagnosis can be made either by direct clinical inspection of infected animals by applying palpation method based on 2 nd and 3 rd stage larvae or by using immunological diagnostic tools. The early diagnosis of hypodermosis is a prerequisite of efficient disease management. Therefore, in the present study, ELISA was performed to diagnose the antibodies to H. lineatum in animal sera. Fifty positive cattle were selected for the collection of larvae L 1 (1st instars) and blood samples. The larvae L 1 (1st instars) were processed for antigen preparation and sera was used for the validation of ELISA. Composition of antigen was determined by using SDS-PAGE. Protein (HyC) was purified by dialysis method and by ion exchange chromatography. Both, crude and purified HyC antigen was used for the ELISA development. One thousand blood samples were taken from the fields. Sensitivity and specificity was calculated from the optical density (OD) of sera. Direct clinical inspection and serology of infested animals were used for monitoring hypodermosis in Northern Punjab (Pakistan). Two hundred cattle with prominent nodules appearing in December - January were selected for comparison between developed ELISA and direct palpation method. The seroepidemiological information was sought out in the prescribed questionnaire having relevant information to generate epidemiological profile. The data from one thousand animals belonging to different villages were recorded based on the epidemiological factors. Seroepidemiological factor like District, village, grazing pattern, sex, type, location, age, breed, previous exposure and herd were studied in the present study. Statistical analysis shows that grazing pattern, location, age, type, xxiiibreed, sex medication and previous exposure has a significant impact in the prevalence of bovine hypodermosis. Geographic Information System (GIS) was used to map the risks factors of hypodermosis in Northern Punjab. GIS risk mapping method was based on herd size, min, max, aver, temperature range, rainfall, relative air humidity and prevalence rate for prediction of the disease. Present study was also proposing the comprehensive information capable of being used for controlling hypodermosis. The geographical map of different districts and villages were developed showing the degree of infestation in different locations. Cluster analysis showed that different area had different zones for the prevalence of bovine hypodermosis. Statistical analysis shows that the temperature in the months of January, February, March, August and November while the precipitation in month of September and October has significant results, when all the risks factors were analyzed. These findings were used for accurate and early diagnosis of bovine hypodermosis, to scan distribution pattern of bovine hypodermosis in Northern Punjab, for the development of suitable control strategies to minimize bovine hypodermosis and to suggest effective control strategies to reduce economic losses. GIS model is also applied for mapping risk area in other agro-ecological regions of Pakistan and developed ELISA which could be used to diagnose bovine hypodermosis in other agro-ecological regions of Pakistan. Vaccination would be suggested by using Hypodermin A antigen to minimize warble fly infestation rate. GIS model can also be applied for mapping risk area and eradication of bovine hypodermosis in other agro-ecological regions of Pakistan.