The profitability of livestock activities can be diminished significantly by the effects of parasites. Economic losses caused by cattle parasites in Brazil were estimated on an annual basis, considering the total number of animals at risk and the potential detrimental effects of parasitism on cattle productivity. Estimates in U.S. dollars (USD) were based on reported yield losses among untreated animals and reflected some of the effects of parasitic diseases. Relevant parasites that affect cattle productivity in Brazil, and their economic impact in USD billions include: gastrointestinal nematodes - $7.11; cattle tick (Rhipicephalus(Boophilus) microplus) - $3.24; horn fly (Haematobia irritans) - $2.56; cattle grub (Dermatobia hominis) - $0.38; New World screwworm fly (Cochliomyia hominivorax) - $0.34; and stable fly (Stomoxys calcitrans) - $0.34. The combined annual economic loss due to internal and external parasites of cattle in Brazil considered here was estimated to be at least USD 13.96 billion. These findings are discussed in the context of methodologies and research that are required in order to improve the accuracy of these economic impact assessments. This information needs to be taken into consideration when developing sustainable policies for mitigating the impact of parasitism on the profitability of Brazilian cattle producers.

Hepatozoon parasites comprise intracellular apicomplexan parasites transmitted to vertebrate animals by ingestion of arthropods definitive hosts. The present work aimed to investigate the occurrence of Hepatozoon spp. in wild animals, domestic dogs and their respective ectoparasites, in southern Pantanal region, central-western Brazil, by molecular techniques. Between August 2013 and March 2015, 31 coatis (Nasua nasua), 78 crab-eating foxes (Cerdocyon thous), seven ocelots (Leopardus pardalis), 42 dogs (Canis lupus familiaris), 110 wild rodents (77 Thichomys fosteri, 25 Oecomys mamorae, and 8 Clyomys laticeps), 30 marsupials (14 Thylamys macrurus, 11 Gracilinanus agilis, 4 Monodelphis domestica and 1 Didelphis albiventris), and 1582 ticks and 80 fleas collected from the sampled animals were investigated. DNA samples were submitted to PCR assays for Hepatozoon spp. targeting 18S rRNA gene. Purified amplicons were directly sequenced and submitted to phylogenetic analysis. A high prevalence of Hepatozoon among carnivores (C. thous [91.02%], dogs [45.23%], N. nasua [41.9%] and L. pardalis [71.4%]) was found. However, ticks and fleas were negative to Hepatozoon PCR assays. By phylogenetic analysis based on 18S rRNA sequences, Hepatozoon sequences amplified from crab-eating foxes, dogs, coatis and ocelots clustered with sequences of H. canis, H. americanum and H. felis. The closely related positioning of Hepatozoon sequences amplified from wild rodents and T. macrurus marsupial to Hepatozoon from reptiles and amphibians suggest a possible transmission of those Hepatozoon species between hosts by ectoparasites or by predation. Hepatozoon haplotypes found circulating in wild rodents seem to present a higher degree of polymorphism when compared to those found in other groups of animals. Although rodents seem not to participate as source of Hepatozoon infection to wild carnivores and domestic dogs, they may play an important role in the transmission of Hepatozoon to reptiles and amphibians in Pantanal biome.

We evaluated if Rickettsia rickettsii-experimentally infected dogs could serve as amplifier hosts for hipicephalus sanguineus ticks. In addition, we checked if Rh. sanguineus ticks that acquired Ri. rickettsii from dogs could transmit the bacterium to susceptible hosts (vector competence), and if these ticks could maintain the bacterium by transstadial and transovarial transmissions. Uninfected larvae, nymphs, and adults of Rh. sanguineus were allowed to feed upon three groups of dogs: groups 1 (G1) and 2 (G2) composed of Ri. rickettsii-infected dogs, infected intraperitoneally and via tick bites, respectively, and group 3 composed of uninfected dogs. After larval and nymphal feeding on rickettsemic dogs, 7.1-15.2% and 35.8-37.9% of the molted nymphs and adults, respectively, were shown by polymerase chain reaction (PCR) to be infected by Ri. rickettsii, confirming that both G1 and G2 dogs were efficient sources of rickettsial infection (amplifier host), resulting in transstadial transmission of the agent. These infected nymphs and adults successfully transmitted Ri. rickettsii to guinea pigs, confirming vector competence after acquisition of the infection from rickettsemic dogs. Transovarial transmission of Ri. rickettsii was observed in engorged females that had been infected as nymphs by feeding on both G1 and G2 dogs, but not in engorged females that acquired the infection during adult feeding on these same dogs. In the first case, filial infection rates were generally <50%. No tick exposed to G3 dogs was infected by rickettsiae in this study. No substantial mortality difference was observed between Ri. rickettsii-infected tick groups (G1 and G2) and uninfected tick group (G3). Our results indicate that dogs can be amplifier hosts of Ri. rickettsii for Rh. sanguineus, although only a minority of immature ticks (<45%) should become infected. It appears that Rh. sanguineus, in the absence of horizontal transmission, would not maintain Ri. rickettsii through successive generations, possibly because of low filial infection rates.

This study evaluates the impact of cattle-raising on ticks associated with wildlife in the Pantanal region of Brazil, by trapping free-living ticks using a CO(2) tick trap. The traps were equally distributed in two areas: a 600-ha protected area (PA) and the Nhumirim Ranch (NR). Both areas are contiguous and located at the sub-region of Nhecolândia (18 degrees 59'S; 56 degrees 39'W), Pantanal, Brazil. In each area, four habitat types were selected: cerrado (tropical savanna), forest patches, lakes and soda lakes. The last two are temporary lagoons of fresh and salted water, respectively. A total of 980 nymphs, 613 adults and 13 larvae of ticks Amblyomma were collected in 256 h of collection. In a pen of calves infested by Ornithodoros rostratus 114 specimens were collected, including larvae, nymphs and adults. Adults of A. cajennense and A. parvum were more abundant in the savanna at NR, but not differed among habitat types at PA. There was a tendency of having more nymphs in NR than in PA. The higher number of ticks found in the NR in comparison to the PA is not due to the presence of cattle itself but probably due to introduced dogs and horses, habitat alteration.

Adult ticks of the species Amblyomma parvum were collected from the vegetation in the Pantanal biome (state of Mato Grosso do Sul) and from horses in the Cerrado biome (state of Piauí) in Brazil. The ticks were individually tested for rickettsial infection via polymerase chain reaction (PCR) targeting three rickettsial genes, gltA, ompA and ompB. Overall, 63.5% (40/63) and 66.7% (2/3) of A. parvum ticks from Pantanal and Cerrado, respectively, contained rickettsial DNA, which were all confirmed by DNA sequencing to be 100% identical to the corresponding fragments of the gltA, ompA and ompB genes of Candidatus Rickettsia andeanae. This report is the first to describe Ca. R. andeanae in Brazil.

The stable fly (Stomoxys calcitrans) has historically been a pest of dairy cattle and feedlots due to the availability of decaying plant matter mixed with animal excrements in such production systems. In the last few decades, stable fly outbreaks have also been reported in pasture-raised beef cattle, usually associated with wastes accumulated from animal feeding during winter, the introduction of large-scale crop operations near cattle ranches, and/or the inadvertent use of organic fertilizers. Population explosions of Stomoxys flies may also have natural causes, affecting not only domestic and/or wild animals but also humans. This article compiles information on stable fly outbreaks in Brazil and abroad and discusses their causes and consequences.Keywords: Stable fly, cattle ectoparasites, bloodsucking flies. ResumoA mosca-dos-estábulos (Stomoxys calcitrans) tem sido historicamente uma praga em gado de leite e gado de corte em confinamento devido à disponibilidade de matéria orgânica vegetal em decomposição, misturada a dejetos animais, nestes sistemas de produção. Nas últimas décadas, surtos de infestação por esta mosca passaram a ocorrer também em rebanhos de corte mantidos extensivamente, geralmente associados ao acúmulo de resíduos de suplementação alimentar durante o inverno, introdução de culturas agrícolas em larga escala no entorno de propriedades pecuárias e/ou uso inadvertido de fertilizantes orgânicos. Eventualmente, explosões populacionais de Stomoxys podem ter causas naturais, afetando animais domésticos e/ou selvagens, além do próprio homem. Este artigo reúne informações sobre surtos da mosca-dos-estábulos no Brasil e em outros países e discute suas causas e consequências.Palavras-chave: Mosca-dos-estábulos, ectoparasitos de bovinos, moscas hematófagas.

The genus Ornithodoros is represented by 15 species in Brazil, on which no detailed life cycle studies have been published, except for O. talaje and O. mimon. The aim of the present study was to evaluate life cycle parameters of O. rostratus based on ticks collected in the Pantanal wetland region of the state of Mato Grosso do Sul, Brazil, using domestic rabbits as experimental hosts. The periods of pre-attachment and feeding of the larvae lasted an average of 39 min (range 15-76 min). Five or six nymphal instars were found. The emergence of adults started with N3 in the following sequence: N3-two males; N4-13 males; N5-three males and 16 females; and N6-two females. Mean weight of N4 that molted to males was 31.7 ± 13.6 mg, whereas mean weight of N5 that molted to females was 100.1 ± 36.2 mg. The overall sex ratio was 1:1. Oviposition lasted 14 days, with a sharp decline beginning with the 7th day. The overall duration of the life cycle of O. rostratus ranged from approximately 66 to 136 days. Comments on the tick-host relationship in the Pantanal region are offered.

The stable fly (Stomoxys calcitrans) and horn fly (Haematobia irritans) are mainly parasites of cattle that spend the early phase of their life cycle in decaying vegetation, manure and soil, as members of a wide range of other harmful and beneficial arthropods. Predators of the family Macrochelidae are considered beneficial mites that have been considered promising biological control agents of fly eggs and larvae and of other harmful organisms. The objectives of this study were: a) to compare the predation and oviposition rates of three Macrocheles species, M. embersoni, M. muscaedomesticae and M. robustulus, on six prey species: S. calcitrans, Musca domestica , H. irritans, Bradysia matogrossensis, Rhizoglyphus echinopus and the free living nematode Rhabditella axei; b) to evaluate the life cycle of the best performing predator (M. embersoni) on the most suitable prey species at 30 ± 2°C, 95 ± 5% RH and in the dark. The three macrochelid species consumed all evaluated prey species, but M. embersoni had higher predation and daily oviposition rates on larvae of S. calcitrans (23.8 larvae consumed and laid about 4.0 eggs, respectively) than other species. Total immature development of M. embersoni was completed in at most about 1.3 days on eggs of S. calcitrans and M. domestica and 1.5 days on R. axei. Macrocheles embersoni produced most eggs (0.28-0.34 female/female/day; r m : 0.28-0.34) on those same prey. The results of this study suggest that M. embersoni is a promising biological control agent of S. calcitrans and M. domestica.