Molecular survey of potentially pathogenic microorganisms in ticks collected from coatis (Nasua nasua) in Iguaçu National Park, Atlantic Forest biome, southern Brazil

Human contact with wild animals in synanthropic habits is often mediated by arthropod vectors such as ticks. This is an important method of spreading infectious agents that pose a risk to human health. Thus, this study aimed to molecularly detect Ehrlichia spp., Anaplasma spp., Borrelia spp., and protozoa of the order Piroplasmida in ticks collected from coatis of Iguaçu National Park (PNI), Paraná, Brazil. This study involved 553 ticks DNA, including Amblyomma spp. larvae, Haemaphysalis juxtakochi nymphs, Amblyomma brasiliense, Amblyomma coelebs, and adults of Amblyomma ovale. The DNA extracted from each sample was subjected to polymerase chain reaction (PCR) targeting the genes 23S rRNA for the Anaplasmataceae family, 16S rRNA for Anaplasma spp., dsb for Ehrlichia spp., flaB, 16S rRNA, hpt, and glpQ for Borrelia spp., and 18S rRNA for Piroplasmid protozoans. DNA from Anaplasma sp. was detected in ticks of the species A. coelebs (4/553); Borrelia sp. DNA was detected in A. coelebs (3/553), A. ovale (1/553), and Amblyomma larvae (1/553); and Theileria sp. was detected in A. coelebs (2/553). All tested samples were negative for Ehrlichia spp. Our study constitutes the newest report in South America of these microorganisms, which remain poorly studied.

Borrelia theileri in Bovine in the northern and southeastern regions of Brazil

The present study aimed to describe the occurrence of Borrelia spp. in cattle in the states of Minas Gerais and Pará in southeastern and northern Brazil, respectively. Bovine whole blood samples were examined by blood smear and polymerase chain reaction (PCR) to detect the flagellin B (flaB) gene of Borrelia spp. Frequencies of positive animals for Borrelia spp. were 1.52% (2/132) in the municipality of Unaí, Minas Gerais, and 14.2% (2/7) in the municipality of Marabá, Pará. Subsequent genetic sequencing confirmed that the detected spirochetes close to the species B. theileri. In both locations, the animals positive for B. theileri were also highly infested by Rhipicephalus microplus ticks. Despite the low frequency of Borrelia spp., the occurrence of this spirochete indicates that further studies are needed to determine the consequences in cattle herds.

Artificial feeding of Ornithodoros rostratus using a silicone membrane system

The in vitro feeding of ticks facilitates the conduction of studies involving the intrinsic vector-pathogen relationship, susceptibility tests, and resistance to acaricides, in addition to mimicking the use of experimental hosts. The objective of this study was to establish an in vitro feeding system using silicone membranes to supply various diets to the species Ornithodoros rostratus. Each experimental group included 130 first-instar O. rostratus nymphs. The groups were divided according to the diet provided: citrated rabbit blood, citrated bovine blood, bovine blood with antibiotics, and defibrinated bovine blood. The control group was fed directly on rabbits. Ticks were weighed before and after the feeding and monitored individually according to their biological parameters. The results of the experiment demonstrated that the proposed system was efficient in terms of fixation stimulus and satisfactory in terms of tick engorgement, which would allow the maintenance of O. rostratus colonies by using artificial feeding through silicone membranes. All diets provided were efficient for the maintenance of colonies, but the ticks that received citrated rabbit blood displayed similar biological parameters to those observed under in vivo feeding conditions.

Survey of bacterial and protozoan agents in ticks and fleas found on wild animals in the state of Rio de Janeiro, Brazil

This study evaluates the presence of bacterial and protozoan agents in ticks and fleas found on wild animals in the state of Rio de Janeiro, Brazil. These ectoparasites were collected on mammal species Hydrochoerus hydrochaeris, Tapirus terrestris, Dicotyles tajacu, Didelphis aurita, Cuniculus paca, Cerdocyon thous, and Coendou prehensilis, and on the terrestrial bird Dromaius novaehollandiae. Ticks and fleas were identified morphologically using specific taxonomic keys. A total of 396 ticks and 54 fleas were tested via polymerase chain reaction (PCR) for the presence of Rickettsia spp., Borrelia spp., microorganisms of the order Piroplasmida and Anaplasmataceae family. This total is distributed among nine tick species of the genus Amblyomma and one flea species. Rickettsia bellii was detected in Amblyomma dubitatum and Amblyomma pacae; Rickettsia sp. strain AL was found in Amblyomma longirostre; Rickettsia parkeri strain Atlantic rainforest was found in Amblyomma ovale; and "Candidatus Rickettsia senegalensis" and Rickettsia felis were detected in Ctenocephalides felis felis. Wolbachia sp. was detected in C. f. felis, and Borrelia sp. was detected in Amblyomma calcaratum (here named Borrelia sp. strain Acalc110). All tested samples were negative for Ehrlichia spp. and microorganisms of the Piroplasmida order. This study detected a new bacterial strain, Borrelia sp. strain Acalc 110 (which is genetically close to B. miyamotoi and B. venezuelensis) and the Rickettsia sp. strain 19P, which is 100% similar to "Ca. R. senegalensis", a bacterium recently discovered and now being reported for the first time in Brazil.

Diversity of tick species (Acari: Ixodidae) in military training areas in Southeastern Brazil

Tick-borne pathogens belong to one of the two main groups of occupational biohazards, and occupational exposure to such agents puts soldiers at risk of zoonotic infections, such as those caused by rickettsiae. There are few studies on acarological fauna and occupational risk in military areas in Brazil. Thus, the present study aimed to analyze the diversity of ticks present in the military training areas of municipalities in the Southeast Region of Brazil. The ticks were collected from the selected areas using the dragging and flagging techniques as well as by visual detection on the operators' clothing, and environmental information was also recorded. A total of ten species were collected from the 66 surveyed areas, belonging to five genera and nine species: Amblyomma sculptum, Amblyomma dubitatum, Amblyomma brasiliense, Amblyomma longirostre, Amblyomma aureolatum, Dermacentor nitens, Rhipicephalus spp., Ixodes spp. and Haemaphysalis spp. The frequent presence of tick species in military training areas along with traces and sightings of wild animals, most commonly capybaras (Hydrochoerus hydrochaeris), in most of the studied areas, indicates high levels of exposure of the military to tick vectors of spotted fever group rickettsiae and the possible occurrence of infections among the troops.

Mastite bovina: Revisão

A mastite é a inflamação da glândula mamária, que gera inúmeras perdas dentro de uma cadeia produtiva, atingindo desde a base, que é a sanidade do rebanho gerando queda da produção, até na qualidade final do leite e seus derivados. A eficiência de um diagnóstico precoce dita o sucesso no tratamento das vacas leiteiras, juntamente com as medidas de prevenção instauradas dentro das propriedades. Diversos métodos são utilizados para a detecção da mastite, visto que esta enfermidade é considerada a doença de maior prejuízo nos rebanhos leiteiros tanto no Brasil quanto no mundo, causando danos aos animais e à saúde pública. Pensando na padronização da qualidade do leite, o Ministério da Agricultura, Pecuária e Abastecimento (MAPA), regulamenta normas que devem ser seguidas através de consultas no Regulamento da Inspeção Industrial e Sanitária de Produtos de Origem Animal (RIISPOA) e através de Instruções Normativas (IN), como as INs 76 e 77, citadas nesse trabalho. O objetivo dessa revisão de literatura é apresentar as principais causas da mastite dentro das propriedades leiteiras, juntamente com os principais meios de diagnóstico, como por exemplo, o teste California Mastitis Test e termografia infravermelha, uma metodologia inovadora, juntamente com as ferramentas mais usadas na prevenção da enfermidade. Além de realizar um levantamento sobre dados atualizados dos prejuízos econômicos gerados pela doença dentro da cadeia produtiva do leite.

Experimental infection of Monodelphis domestica with Rickettsia parkeri

This study aimed to evaluate the infection of the marsupial Monodelphis domestica (the gray short-tailed opossum) by Rickettsia parkeri and its role as an amplifier of the bacterium for Amblyomma ticks. Ten M. domestica males were inoculated with phosphate-buffered saline (PBS) and 10⁶ Vero cells infected with R. parkeri. In seven animals, inoculation was intramuscular, and in three intraperitoneal. One male (control) received 1 ml of the same vehicle used for inoculation intraperitoneally. The three animals inoculated intraperitoneally were infested with uninfected A. sculptum larvae and nymphs between the 2^nd and 9^th day post-infection (DPI). Parasitemia was monitored from the 3^rd to 9^th DPI by polymerase chain reaction, using primers for 17 kDa and ompA. The animals were also clinically evaluated. Of the animals infected intramuscularly, only one was blood-positive by the 5th DPI. The three animals infected intraperitoneally were blood-positive on the 2nd, 5th, 7th, and 9th DPI. Of the ten pools of recovered engorged ticks, six had positive bands. The kidney, liver, heart, and spleen of an intramuscularly infected animal were also positive. The rectal temperature of the animals tested increased only in the first three DPI. The animals inoculated intraperitoneally showed prostration, bristled hair, and weight loss. The study found that R. parkeri was capable of infecting M. domestica, which developed rickettsemia and caused infection in xenodiagnostic ticks.

Experimental infection of Rickettsia parkeri in the Rhipicephalus microplus tick

This study aimed to evaluate, by means of artificial feeding, the interaction between a pathogenic rickettsia and the hard tick R. microplus. We used partially engorged females fed on calves free of Rickettsia spp. Group 1 (G1), containing 20 ticks, was fed bovine blood only. Group 2 (G2), containing 20 ticks, was fed blood containing uninfected VERO cells, and group 3 (G3), containing 40 ticks, was fed blood containing VERO cells infected with Rickettsia parkeri. Biological parameters of the non-parasitic phase and a possible bacterial transmission to the tick eggs and to guinea pigs were evaluated. At the end of oviposition, all G3 females were PCR-positive for genes specific for the genus Rickettsia. Although no guinea pigs were infected, the experimental infection of R. microplus by R. parkeri caused a deleterious effect on the oviposition and provided the first report of transovarian transmission of rickettsia in this tick.

Using plastic tips in artificial feeding of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) females

This study evaluated the influence of the initial weight, feeding period and temperature on weight gain and biological parameters of the non-parasitic phase of partially engorged Rhipicephalus sanguineus females that were artificially fed using plastic tips as feeding devices. The device did not alter the oviposition of the females or any other parameters evaluated. Furthermore, it was observed that the temperature of the feeding the group did not affect the weight gain and biology of ticks. This device has great potential for the development of studies on bioagent transmission because it provides higher intake of blood by ixodid ticks.

Analysis of the risk factors relating to cows' resistance to Rhipicephalus microplus ticks during the peripartum

This study aimed to evaluate season, breed, number of lactations and milk production as risk factors relating to Rhipicephalus microplus infestation in dairy cows during the peripartum. Eighty-four animals were randomly selected through proportional stratified sampling. All engorged and partially engorged female R. microplus specimens measuring 4.5-8.0 mm were counted during the 5 weeks before calving, calving week and 5 weeks after calving. The peripartum had a significant effect [calving (p < 0.05; prevalence ratio (PR)= 3.12) and post calving (p < 0.05; PR = 2.02)] on R. microplus infestation. Although the average tick count was higher during the rainy season than during the dry season, there was no significant difference (p = 0.055; PR = 0.63). The average R. microplus count was significantly higher (p < 0.05; PR = 2.10) in Bos taurus animals, followed by F1 (p < 0.05; PR = 1.64) and Girolando (p < 0.05; PR = 1.39). The average R. microplus count was significantly higher (p < 0.05; PR = 0.97) in first-lactation animals, followed by those at the second, third and, fourth or subsequent lactation. Milk production showed a negative correlation with R. microplus count, such that high-production animals were significantly (p = 0.003; PR = 2.04) more vulnerable to infestation than were low-production animals. First-lactation and high-production B. taurus animals had greatest vulnerability to R. microplus infestation over the peripartum period, and constituted the at-risk group in the dairy herd.

Influence of the physiological state on infestation by Rhipicephalus microplus in dairy cows

The purpose of this study was to identify the influence of physiological state, season, breed, number of lactations, dairy productivity, and stocking rate on infestation by Rhipicephalus microplus in dairy cows. Two hundred cows were selected through proportional representative sampling at the Seropédica Experimental Station (Pesagro-Rio), Brazil. Fully or partially engorged R. microplus females measuring between 4.5 and 8.0mm were counted on the right side of each animal. The tick infestation prevalence data were analyzed in relation to the risk factors, using multiple logistic regression. Associations between prevalence and its possible influencing determinants were measured using odds ratios. The average tick count of cows during the peripartum and lactation periods was significantly higher (p<0.05; OR=4.82) than the count in dry cows. Taurine animals showed significantly higher infestation (p<0.05; OR=3.28) than pure zebuine animals. Among cross-bred animals, the infestation was higher (p<0.05) in F1 animals (1/2 taurine×1/2 zebuine) than in Girolando animals (5/8 zebuine×3/8 taurine). Primiparous cows (p<0.05) had significantly heavier infestations than multiparous cows. Dairy production showed a positive correlation with tick infestation (p<0.03; OR=2.94), such that the most productive animals were the most parasitized ones. Animals kept at high densities were significantly more heavily infested (p<0.05, OR=6.32) than animals kept at low density. First-lactation and high-productivity taurine animals were more vulnerable to R. microplus, thus comprising a high-risk group in dairy herds.

Risk factors relating to helminth infections in cows during the peripartum

The aim of this study was to investigate whether season, lactation number, breed standard and milk production were risk factors relating to occurrences of gastrointestinal nematodes in dairy cows during the peripartum period. Eighty-four cows were randomly selected through proportional stratified sampling. In order to analyze the fecal egg per gram (EPG) count, the data were subjected to the Spearman test, Kruskal-Wallis test at 5% significance and linear regression. At the time of calving, the cows showed high EPG counts in relation to all variables analyzed. Among the animals studied, we observed that purebred Holstein cows at their first lactation and with high milk production showed high EPG counts (600) and comprised the group most at risk within the herd studied. In this group, the animals showed moderate EPG during the prepartum period (300) and a significant increase (p < 0.01) in EPG count from the time of calving (900), i.e. an increase of the order of 300%. Selection of animals for milk production in tropical countries should be based not only on productive potential, but also on adaptive features.