Serosurvey of spotted fever group Rickettsia in equids from western Pará, Amazon, Brazil.

From a previous large epidemiological survey, we randomly selected 474 serum samples (463 horses and 11 mules) distributed among four municipalities of Pará state, Amazon region, Brazil, and from three types: farm animal, urban carthorse, and sport horse. Samples were tested by indirect fluorescence antibody test (IFAT ≥ 64) for antibodies reactive to spotted fever group (SFG) rickettsiae using Rickettsia rickettsii as crude antigens. From the 474 equids tested, 149 (31.4%) had ticks attached during sampling, belonging mostly to the species Dermacentor nitens. The overall seroprevalence for SFG rickettsiae was 31.4% (95% confidence interval: 27.3-35.9%) with 149 seropositive animals out of 474 screened. Notably, 77 equids (16.2%) had high endpoint titers ranging from 512 to 16,384, indicating that they had been exposed to SFG rickettsiae not long before sampling. Animal type affected rickettsial seroprevalence, with significantly higher values among farm horses when compared with urban and sport animals. Presence of dogs and tick infestation were negatively associated with equid seropositivity to R. rickettsii. This is the first report of SFG rickettsiae-reactive antibodies in equids from Pará state, Brazilian Amazon.

Factors associated with the prevalence of antibodies against Brucella abortus in water buffaloes from Santarém, Lower Amazon region, Brazil.

We evaluated the factors associated with the prevalence of antibodies against Brucella abortus in buffaloes in the municipality of Santarém, Western Pará, northern Brazil. The study was conducted on 60 farms, representing 25.8% of the total buffalo farms in the region. From those farms, a total of 426 buffaloes were sampled, males of any age and females more than 24 months of age, to avoid a false-positive reaction in the serological test due to vaccination. The Acidified Agglutination Serum Test was carried out on serum samples using B. abortus strain 1,119-3 as the antigen. Univariate and multivariate analysis were performed to investigate the association between brucellosis and potential risk factors. Of the 426 tested buffaloes, 29 were positive, resulting in an overall animal prevalence of antibodies against B. abortus at the animal level of 6.8% (4.6-9.6; 95% confidence interval). The herd level prevalence was 30% (18 of 60) and seroprevalence range within farms was from 0% to 100%. At the animal level, buffaloes raised in the floodplains tended (p = 0.06) to present a higher seroprevalence (9.70%) of antibodies against B. abortus than buffaloes raised in dry land (4.98%) and cows tended (p = 0.054) to have a higher seroprevalence than male buffaloes. Multivariate herd-level analysis revealed association between farm type and brucellosis seroprevalence (p = 0.015); dairy farms were two times more likely to have seropositive buffalo than beef farms. Our survey demonstrated a high farm seroprevalence of B. abortus in buffalo raised in an Amazonian ecosystem with positive animals found in one third of sampled farms.

Factors associated with the prevalence of antibodies against Theileria equi in equids of Western Pará, Brazil.

The State of Pará has one of the largest herds of equids (horse, donkey and mule) in Brazil, most of these animals are found on cattle farms. Equine theileriosis is a tick-borne disease caused by the parasite Theileria equi and is characterized by fever, anaemia, icterus, intravascular haemolysis, haemoglobinuria, spleen and hepatomegaly, and even death. The present study aimed to determine the prevalence of antibodies against T. equi in equids in the western region of the State of Pará, Brazil, and to identify potential risk factors associated with parasite infection. A cross-sectional study was conducted with cluster sampling of farm horses from 18 municipalities. In the cities visited, samples from sport and carthorses were also included. Serum was obtained to detect T. equi-specific antibodies using an indirect enzyme-linked immunosorbent assay (iELISA) based on a crude parasite antigen. In order to identify possible risk factors of the infection which are associated with the prevalence of antibodies, a chi-squared test was carried out. Of 1,117 equids, 373 tested positive for T. equi antibodies with an overall prevalence of 33.4% (31.3%-37.0% for the 95% confidence interval). Sex, animal species and breed were found not to be associated with the presence of T. equi antibodies, whereas age, the presence of dogs or ticks were associated with seropositivity (p < 0.05). Horses with ticks were 2.4 more likely seropositive than horses without ticks. The presence of dogs in the equid habitat and the presence of ticks resulted in a higher T. equi seropositive rate probably because dogs are hosts for vector ticks of T. equi. Our study represents the first report of T. equi antibodies in equids of western Pará revealing a widespread distribution of seropositive animals.

Prevalence of antibodies against Toxoplasma gondii and Neospora spp. in equids of Western Pará, Brazil.

The present study aimed to determine the prevalence of antibodies against Toxoplasma gondii and Neospora spp. in equids raised for distinct purposes in the western state of Pará, Brazil, and to identify potential risk factors associated with parasite infection. A cross-sectional study was conducted with cluster sampling in 101 farms from 18 municipalities (farm horses). In visited municipalities, samples from sport and cart horses were included. Serum was obtained for detecting antibodies against T. gondii and Neospora spp. using indirect fluorescent antibody test, with a cut-off point of 1:64 and 1:50, respectively. Association analysis, using the chi-square test, was performed to evaluate possible risk factors related to the prevalence of antibodies. A total of 1298 equids were sampled (947 farm, 240 sport, and 111 cart horses), including 1244 horses, 2 donkeys, and 52 mules. The number of equids sampled per property ranged from 1 to 49. Of the total examined, 134 (10.3%) had antibodies against T. gondii, and of the 18 municipalities visited, 11 (61%) had at least one positive animal. Seventy-three of the 1298 equids (5.62%) from 44% of the municipalities tested positive for Neospora spp. The type of the animal (farm, sport, or carthorse) was not associated with the prevalence of antibodies against T. gondii; however, antibodies against Neospora spp. was more prevalent in carthorses (P = 0.001) (13.5%) than in farm (5.0%) and sport (4.6%) horses. Breed of the horse and the presence of cats were risk factors for the prevalence of antibodies against T. gondii, and presence of dogs was a risk factor for the prevalence of antibodies against Neospora spp. This is the first report of seropositive equids for T. gondii and Neospora spp. in the state of Pará contributing to the knowledge on epidemiology of the two parasites.

Novel piroplasmid and Hepatozoon organisms infecting the wildlife of two regions of the Brazilian Amazon.

During 2009-2012, wild animals were sampled in two areas within the Amazon biome of Brazil, in the states of Mato Grosso and Pará. Animal tissues and blood were molecularly tested for the presence of Piroplasmida (genera Babesia, Theileria, Cytauxzoon) or Hepatozoon DNA. Overall, 181 wild animals comprising 36 different species (2 reptiles, 5 birds, and 29 mammals) were sampled. The following Piroplasmida agents were detected: Cytauxzoon felis in one ocelot (Leopardus pardalis), Theileria cervi in two red brocket deer (Mazama americana), Theileria spp. in three nine-banded-armadillos (Dasypus novemcinctus), one agouti (Dasyprocta sp.), and four lowland pacas (Cuniculus paca), Babesia spp. in one common opossum (Didelphis marsupialis) and one white-lipped peccary (Tayassu pecari). The following Hepatozoon agents were detected: Hepatozoon sp. (possibly Hepatozoon caimani) in three spectacled caimans (Caiman crocodilus), Hepatozoon felis in an ocelot (Leopardus pardalis), and Hepatozoon spp. in one scorpion mud turtle (Kinosternon scorpioides) and one lowland paca (Cuniculus paca). Phylogenetic analyses inferred by the 18S rRNA gene partial sequences supported these results, highlighting at least five novel Piroplasmida agents, and two novel Hepatozoon agents. This study screened the presence of tick-borne protozoa in a number of wildlife species from the Amazon for the first time. Our results indicate that a variety of genetically distinct Piroplasmida and Hepatozoon organisms circulate under natural conditions in the Amazonian wildlife.

Seroprevalence of Tick-Borne Pathogens and Tick Infestation in Dogs from Tapirapé and Karajá Indigenous Communities, Brazil.

With the aim of studying some tick-borne diseases, a total of 327 dogs (114 from Tapirapé and 213 from Karajá indigenous ethnicity, Mato Grosso, MT, Brazil) were sampled. Serum samples were submitted to the indirect fluorescence antibody test (IFAT) to detect antibodies against Babesia vogeli, Ehrlichia canis, and Rickettsia spp. Possible associations of risk factors and the occurrence of seroreativity to tick-borne agents and tick infestations were analyzed through chi-squared tests. Among 327 dogs, 46 (13.15%) were seropositive for B. vogeli and 47 (14.37%) for E. canis. The B. vogeli seroprevalence was higher for Karajá and for adult dogs (p>0.05). No association was found for E. canis seroprevalence. From 103 serum samples tested with rickettsial antigens, 90 (87%) dogs were seropositive to Rickettsia spp., with highest reactivity to Rickettsia amblyommii. Canine seropositivity to Rickettsia spp. was associated (p<0.05) with ethnicity (higher seroprevalence in Tapirapé dogs), age (higher in adults), and hunting (higher among hunting dogs). From the 327 dogs, 39 (11.9%) were infested by ticks (Amblyomma cajennense sensu stricto, Amblyomma ovale, Amblyomma oblongoguttatum, Amblyomma tigrinum, and Rhipicephalus sanguineus). Infestations by Amblyomma spp. ticks were higher in dogs from Tapirapé community and in hunting dogs (p<0.05). Regarding R. sanguineus, infestations were higher (p<0.05) among young dogs.

Clinical response and transfusion reactions of sheep subjected to single homologous blood transfusion.

Studies in relation to blood conservation and responses to transfusion are scarce for ruminants. We evaluated the clinical manifestations of sheep that received a single homologous transfusion of whole blood, focusing on transfusion reactions. Eighteen adult sheep were subjected to a single phlebotomy to withdraw 40% of the total blood volume, which was placed into CPDA-1 bags and then divided into G0, animals that received fresh blood, and G15 and G35, animals that received blood stored for 15 or 35 days, respectively. Clinical observations were recorded throughout the transfusion, whereas heart rate, respiratory rate, and rectal temperature were assessed at the following times: 24 hours after phlebotomy and before transfusion; 30 minutes, six, twelve, 24, 48, 72, and 96 hours and eight and 16 days after transfusion. All groups presented transfusion reactions, among which hyperthermia was the most frequent (50% of animals). Tachycardia occurred most frequently in the G35 animals (50% of them). During transfusion G35 animals presented more clinical manifestation (P < 0.05). Transfusion of fresh or stored total blood improved the blood volume, but transfusion reactions occurred, demonstrating that a single transfusion of fresh or stored blood can cause inflammatory and febrile nonhemolytic transfusion reactions in sheep.