Molecular and Serological Survey of Toxoplasmosis in Iranian`s Small Ruminants

Background: The parasitic disease toxoplasmosis is brought on by the compilation protozoan agent Toxoplasma gondii and can result in substantial losses in terms of quality-adjusted life years and monetary damages. Consuming raw or overcooked meat has been a major source of transmission.

Aim: The present study was conducted to survey the frequency of T. gondii in livestock meat (sheep and goats) by using a MAT test and compare it with polymerase chain reaction (PCR) methods as well as to determine the genetic diversity of infecting strains of T. gondii.

Methods: This cross-sectional study was conducted in Quchan city in Khorasan Razavi province in northeastern Iran. Blood and tissue samples (diaphragm, heart) of 296 animals (including 168 sheep and 128 goats) were collected from the slaughterhouse in Quechan City from August 2016 to April 2017. Serum samples were examined by the Modified agglutination test (MAT) and the Nested-PCR method performed to amplify the fragment of the B1 gene to detect parasite DNA on tissues of seropositive animals. PCR-RFLP method of the GRA6 gene was used to determine the genotype of T. gondii. Also, sequencing analysis was performed to evaluate the Toxoplasma-type strains.

Results: Serum positive for MAT results were found in 27.4% of Sheep and 23.4% of goats. Positive Nested-PCR of the B1 gene results in diaphragm and heart tissues of sheep and goats were 47.8% and 26.1%, 40% and 23.3%, respectively. Nested-PCR of GRA6 gene results were positive in 10 samples that RFLP technique results using MseI enzyme revealed genotype I. Sequencing and Phylogenetic analysis revealed DNA of all samples was closely related to Toxoplasma type I.

Conclusion: Given the high seropositivity rate of toxoplasmosis, it is advised to implement a suitable preventative program to lower the incidence of T. gondii infection through cattle intake of raw or undercooked meat. Our research lends credence to the idea that the intake of raw or undercooked meat by these animals may be a potential source of toxoplasmosis in humans.