Natural infection by Anaplasma marginale during the first weeks of life of calves on a dairy farm in the eastern Amazon

Autor: Maiara Vasconcelos Monteiro, Danillo Henrique da Silva Lima, Matheus Dias Cordeiro, Bruna de Azevedo Baêta, Izabela Mesquita Araújo, Maria Hilma Soares Sodré, Mário José Costa Carneiro, Nailson de Andrade Neri Junior, Ediene Moura Jorge, Paulo Cesar Magalhães-Matos, José Diomedes Barbosa Neto, Natália da Silva e Silva Silveira
Jazyk: English<br />Portuguese
Rok vydání: 2024
Předmět:
Zdroj: Ciência Rural, Vol 54, Iss 8 (2024)
Druh dokumentu: article
ISSN: 1678-4596
0103-8478
DOI: 10.1590/0103-8478cr20230255
Popis: ABSTRACT: This study detected Anaplasma marginale in calvesusing blood smears and nested PCR (nPCR) and to compare the results with the clinical signs presented by calves on a dairy farm in the municipality of Castanhal, located northeast of the state Pará (1°07’19.1”S and 47°53’53.0”W), eastern Amazon. To this end, 192 blood samples were collected from 24 animals at 1-20, 21-41 and 42-60 days of age. Blood smears and nPCR with primers for the msp5 gene were performed. The prevalence of A. marginale was 61.5% (118/192) for the blood smear technique and nPCR (msp5). The manifestation of clinical signs of anaplasmosis also increased significantly over the course of the study (P < 0.0001), being lower in animals aged 1-20 days, but increasing among those aged 21-41 and 42-60 days. These signs were characterized by apathy, fever, weight loss, diarrhea, dehydration, and hypochromic mucous membranes. Regarding the evaluation of the diagnostic techniques, no significant difference was observed in the detection of A. marginale between the blood smear and nPCR (P = 0.995), but the agent’s rickets increased on Day 47 (P < 0.01) in both tests, thereby demonstrating a near-linear pattern of increase in rickets over the 60 days, with a consequent decrease in globular volume. This shows that of the 24 animals studied, 21 were infected at some point during the study period. Additionally, there was no significant difference between blood smears and nPCR, probably due to medium and high parasitemia, which were directly related to the clinical signs and decrease in globular volume.
Databáze: Directory of Open Access Journals
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