Age and sex distribution of Dirofilaria immitis among dogs in Meshkin-Shahr, northwest Iran and molecular analysis of the isolates based on COX۱ gene

Dirofilaria immitis is an important filarial nematode in dogs. In this study, age and sex distribution of this zoonotic nematode among dogs were investigated in northwest of Iran in Meshkin-Shahr city. Molecular characteristics of the isolates, based on cytochrome oxidase subunit ۱ (COX۱) gene were compared to the isolates from other areas of the world.Blood samples were collected from ۹۱ dogs which were selected by simple classified accidental sampling. Thin and thick blood smear examinations were used to find out infectivity with D. immitis. DNA extraction was performed from adult D. immitis recovered from heart of infected dogs. The COX۱ gene was amplified and sequenced. Phylogenetic analysis was carried out using sequences obtained in this study along with relevant sequences deposited in the GenBank. Phylogenetic analysis and sequence variation was performed using MEGA software in comparison with those COX۱ sequences deposited in GenBank. Out of ۹۱ dogs, ۱۹ (۲۰.۸۷%) were found positive for infection with D. immitis. There was no statistically significant difference between males and females of dogs in terms of D. immitis infection. However, the rate of infection in dogs more than ۲ years old was significantly higher than those with lower age. Both sequences analyzed in this study showed ۱۰۰% homology to each other. Intra-species variation of these isolates with those from other areas of the world amounted to ۰ to ۰.۵۰%. Phylogenetic analysis of the COX۱ gene suggested that it is conserved, and can be used for study on genetic diversity and classification of filarial nematodes.

کلیدواژه ها:

Dirofilaria immitis ، Dog ، Meshkin-Shahr ، Molecular analysis