A study on Dirofilaria immitis in healthy urban dogs from Ahvaz, Iran

Abstract

Summary Heartworm infection is one of the most important p arasitic diseases in dogs and an increasing number of cases are reported each year by necropsy in Ahvaz. This study was conducted to determine the prevalenc e of Dirofilaria immitis infection and to investigate the risk factors rela ted to heartworm disease in urban dogs in this area. Blood samples were collected from 100 dogs from Feb 2007 to Feb 2008. All samples were examined by modified Knott test, direct smear and a ntigen detection (Immunochromatographic antigen rapid canine D. immitis Ag Test Kit) technique to detect circulating micro filaria and adult antigen of D. immitis , respectively. Of the total 100 dogs, 1% were positi ve by direct smear, 5% were positive by modified Knott test and 6% were positive by antigen detection. In addition, 1% of positive dogs were determined to ha ve occult D. immitis infections. Dirofilaria immitis was the only canine filarial parasite present in t his study. From these three methods, modified Knott test, due to microfilarial identification on concentrated blo od had the highest validity. The difference between outdoo r and indoor dogs was found significant (P = 0.033) , whereas no statistically significant differences we re observed between different age groups, sexes and breeds (P>0.05). The highest heartworm prevalence by modified Knott test was observed in older than 6-year-ol d dogs (8.3%) followed by 3‐6 years (2.7%) and the 6-month to 3 years (3.5%) age groups. The infection w as more prevalent in males and short haired breeds. Ou r results suggest that heartworm treatment and prev entive care should be considered in urban dogs of Ahvaz, I ran.