Detecção sorológica, molecular e diversidade genética de Anaplasma spp. em pequenos ruminantes da microrregião do Baixo Parnaíba, Maranhão

Abstract

Anaplasmosis, caused by bacteria of the genus Anaplasma, is an important disease transmitted by ticks that cause damage to livestock farms in many countries. Goats and sheep are susceptible to infections by bacteria of this genus and have been widely reported in different regions of the world. Despite the importance of this pathogen for animal health, little research has been carried out in order to detect the occurrence of this pathogen in small ruminants in Brazil. Thus, this research aimed to detect and determine the genetic diversity of Anaplasma spp. in small ruminants from the Baixo Parnaíba Maranhense region. For this, blood samples were collected from 161 animals, 70 sheep and 91 goats, from 4 municipalities in the Baixo Parnaíba region, all clinically healthy at the time of collection. Blood smears, stained with Giemsa, were made to observe inclusions of Anaplasma spp. by light microscopy. The serum of sheep and goats was subjected to serological diagnostic methods, using iELISA, recombinant membrane surface protein (MSP5) and blood, to the molecular diagnosis for the detection of A. marginale using qPCR and snPCR. Positive samples were then sequenced and then subjected to analysis of genetic diversity by RepeatAnalyzer program. Thus, it was not possible to observe inclusions suggestive of Anaplasma spp. in any of the blood smears analyzed. The serological survey detected the presence of anti-A. marginale antibodies in 18 animals (11.1%), with 2.8% goats and 17.5% sheep. It was possible to identify the DNA of A. marginale in 2 sheep (1.24%) using qPCR. These positive samples were then subjected to snPCR, based on the msp1α gene, and both were positive. The sequencing analysis of the samples showed identity percentages ranging from 90.97% to 98.79% with A. marginale, and with respect to genetic diversity, two distinct strains α 􀈕 and α β Γ;γ;Γ;γ;Γ;γ;Γ;γ, were characterized, each in a different animal, never reported in small ruminants, both belonging to the H genotype and with respect to genetic diversity, two distinct strains were characterized, each in a different animal, never reported in small ruminants. Both strains belonging to the H genotype. High genetic diversity of the strains was demonstrated among themselves and in the studied region. Based on the above, it was possible to confirm the circulation of A. marginale in sheep and goats in the State of Maranhão, using the serological and molecular approaches