BackgroundBrazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, has been associated with the transmission by the tick Amblyomma sculptum, and one of its main hosts, the capybara (Hydrochoerus hydrochaeris).MethodsDuring 2015–2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome, all with established populations of capybaras.ResultsThe BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, when compared to the BSF-nonendemic areas. Only two tick species (A. sculptum and Amblyomma dubitatum) were found in the anthropic areas; however, with a great predominance of A. sculptum (≈90% of all ticks) in the endemic areas, in contrast to a slight predominance of A. dubitatum (≈60%) in the nonendemic areas. Tick species richness was higher in the natural areas, where six species were found, albeit with a predominance of A. sculptum (≈95% of all ticks) and environmental tick burdens much lower than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. In contrast, the BSF-nonendemic areas with landscape similar to the endemic areas differed by having lower tick burdens and a slight predominance of A. dubitatum over A.sculptum, both sustained chiefly by capybaras. While multiple medium- to large-sized mammals have been incriminated as important hosts for A. sculptum in the natural areas, the capybara was the only important host for this tick in the anthropic areas.ConclusionsThe uneven distribution of R. rickettsii infection among A. sculptum populations in highly anthropic areas of São Paulo state could be related to the tick population size and its proportion to sympatric A. dubitatum populations.

In the present study, 256 7-wk-old Japanese quail were randomly distributed into four experimental groups (64 birds per group) and given rations containing 0 (controls), 25, 50, or 100 (g aflatoxin B, (AFB1)/kg feed for 168 d. Each treatment consisted of four replicates of 16 quail. Egg production and individual egg weight were checked daily. Feed consumption and feed use were determined weekly. Eggs laid in the last day of each 28-d laying period were collected and subjected to individual analysis for specific gravity, Haugh units, shell thickness and percentage eggshell. Results showed that average egg production, feed use, and body weights were not affected (P > 0.05) by AFB1. However, feed consumption was lower (P < 0.05) for groups fed 50 or 100 microg AFB1/kg. Egg weight was significantly lower (P < 0.05) only for groups exposed to 50 and 100 microg AFB1/kg. Average egg specific gravity, Haugh units, and shell thickness were not affected (P > 0.05) by AFB1. Percentage eggshell was higher (P < 0.05) in the group fed the ration containing 100 microg AFB1/kg. Treatment associated lesions were observed only in the liver. Hepatic cell vacuolation with fatty infiltration was observed in all liver samples of quail fed AFB1-contaminated rations. Bile duct proliferation and trabecular disorder were found only in livers of quail on the 100-microg AFB1/kg treatment. Results indicated that chronic exposure to AFB1 at levels above 50 microg/kg could adversely affect quail performance, emphasizing the importance of controlling aflatoxin contamination in quail rations.

RESUMO

Detailed cleaning and disinfection programs aims to reduce infection pressure from microorganisms from one flock to the next. However, studies evaluating the benefits to poultry performance, the sanitary status of the facilities, and the sanitary quality of the meat are rarely found. Thus, this study was designed to evaluate 2 cleaning and disinfecting programs regarding their influence on productive performance, elimination of Campylobacter, and characterization of Campylobacter jejuni strains when applied to broiler chickens’ facilities. Two subsequent flocks with 960 birds each were distributed into 32 pens containing 30 birds each. In the first, the whole flock was inoculated with a known strain of Campylobacter jejuni in order to contaminate the environment. In the second flock, performance and microbiological evaluations were done, characterizing an observational study between 2 cleaning and disinfection programs, regular and proposed. The regular program consisted of sweeping facilities, washing equipment and environment with water and neutral detergent. The proposed cleaning program consisted of dry and wet cleaning, application of 2 detergents (one acid and one basic) and 2 disinfectants (250 g/L glutaraldehyde and 185 g/L formaldehyde at 0.5% and 210 g/L para-chloro-meta-cresol at 4%). Total microorganism count in the environment and Campylobacter spp. identification were done for the microbiological assessment of the environment and carcasses. The positive samples were submitted to molecular identification of Campylobacter spp. and posterior genetic sequencing of the species identified as Campylobacter jejuni. The birds housed in the facilities and submitted to the proposed treatment had better performance when compared to the ones in the regular treatment, most likely because there was a smaller total microorganism count on the floor, walls, feeders and drinkers. The proposed program also resulted in a reduction of Campylobacter spp. on floors, drinkers and birds. Moreover, it was possible to identify 6 different Campylobacter jejuni strains in the facilities. The proposed treatment resulted in a positive influence on the birds’ performance and reduction of environment contamination for broiler chickens.