Epidemiological Spectrum of Bovine Tick-Borne Pathogens in Northeast Brazil: Comparative Analysis Across a Tropical Humid and Two Semi-Arid Regions

TL;DR

This study examines the spread of tick-borne cattle diseases in different regions of Brazil, finding high infection rates and identifying risk factors like fly presence and poor management practices.

Contribution

The study provides a comparative analysis of tick-borne pathogen epidemiology across distinct climatic regions in Brazil, identifying region-specific risk factors and infection patterns.

Findings

Infection rates were highest in the tropical humid region of Paraíba at 94.8%.

Co-infections, especially with A. marginale and B. bigemina, were common, with triple infections occurring in 15.8% of animals.

Risk factors included horn fly presence, needle reuse, and lack of quarantine for newly purchased cattle.

Abstract

Cattle tick fever (CTF), caused by Anaplasma marginale, Babesia bovis and Babesia bigemina, remains a sanitary and economic challenge for cattle farming in Brazil. Thus, this study evaluated the prevalence, regional distribution, co-infection patterns, and risk factors associated with CTF causative agents in cattle the semi-arid region of Paraíba, the semi-arid region of Ceará, and the Tropical Humid region of Paraíba, Northeast Brazil. Blood samples were collected from 336 cattle, from 60 farms, and analyzed by means of conventional PCR and nested-PCR, while epidemiological data were obtained through questionnaires applied to producers. The overall infection prevalence by at least one pathogen was 82.7% (278/336), with higher rates in the tropical humid region of Paraíba at 94.8% (109/115), followed by the semi-arid region of Ceará, with 88.1% (89/101) and the semi-arid region of Paraíba with 66.6% (80/120). Co-infections were frequent, especially the association between A. marginale and B. bigemina, detected in 23.2% (78/336) of the animals, while triple infections occurred in 15.8% (53/336) and were most frequent in the semi-arid region of Ceará at 21.8% (22/101). The semi-arid region of Paraíba had the fewest entirely positive properties (7/20) and the highest number of entirely negative properties (2/20). The tropical humid region of Paraíba had the highest number of entirely positive properties (17/21), with no properties entirely free of CTF agents. Multivariate analysis identified the presence of horn fly (OR = 7.23; CI 3.05–18.86; 95% CI), needle reuse (OR = 5.8; CI: 2.62–13.90; 95% CI), animal purchase and introduction without quarantine (OR = 5.4; CI: 2.17–14.93; 95% CI), and pasture sharing (OR = 3.21; CI: 1.08–11.25; 95% CI) as risk factors, while beef herds showed lower susceptibility (OR = 0.28; CI: 0.15–0.52; 95% CI). These findings demonstrate that infections by CTF causative agents are endemic but exhibit region-specific epidemiological patterns, reflecting the combined effects of climate and management practices, and localized transmission foci that may be intensified by commercial cattle movement.

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