A retrospective perspective on epidemiology, clinicopathological and therapeutic aspects of microfilariosis in buffaloes of West Godavari District, Andhra Pradesh.

Utilizing retrospective data collected over a period of nine years during the period from 2010 till 2019, an attempt was made to study various aspects of microfileremia in adult buffaloes in West Godavari district of Andhra Pradesh. This study involves an analysis of epidemiological aspects of microfilariosis, clinical presentation and therapeutic efficacy of Ivermectin. The study involved initial examination of 15,851 blood samples of buffaloes collected in the district from different sources and various predisposing factors influencing the incidence like season, stocking density, vector propagation, individual and herd stressors, age and lactation status were considered. Diagnostic specificity and applicability of available tests like wet blood smear examination, methylene blue staining, Giemsa's staining and Modified Knott's test were evaluated. The incidence was highest during July-September (6.6%) followed by October-December (6.1%), January-March (5.2%) and April-June (4.9%). Post monsoon warm and humid weather appears to favour the vector propagation and incidence. High proportion of microfilaremia at least 2-3 per alternate microscopic fields was presumed to be responsible for clinical microfilariosis than low infection like one motile parasite for every 3-6 microscope fields. Fourteen (14) clinical cases and equal number of healthy control animals, both are lactating, calved 4-5 month back, with an average milk yield of 6.8 L were selected for clinical studies and evaluation of hematological and biochemical parameters. Therapeutic efficacy of Ivermectin was evaluated by assessing the circulatory clearance rate of microfilaria, improvement in clinical signs and return to productivity. The possibility of spontaneous elimination of parasite without specific treatment was not considered with an aim for rapid recovery without complications. Supportive therapy aided in the correction of anemia and speedy recovery. Recurrence of microfileremia was not observed after two months of periodic post therapeutic evaluation and follow-up.