Report of Amblyomma sculptum in a House in a Rickettsia rickettsii Circulation Area.

Amblyomma sculptum is a tick that has medical and veterinary importance as, in Brazil, it is the main vector of Rickettsia rickettsii, a disease affecting humans. The presence of ticks was observed outside a residence in a peri-urban area of the Atlantic Forest region in Brazil, as well as on two dogs that lived there. Eighteen A. sculptum adults were seen walking on a cemented pillar at the porch of the house and sheltering inside the pillar's crevices; meanwhile on the dogs, only Rhipicephalus sanguineus sensu lato ticks were found. It is hypothesized that as the dogs circulated in the forest regions, they might have carried A. sculptum to the residence. This situation highlights the role of dogs as possible carriers of Brazilian spotted fever (BSF) tick vectors into human habitation. Strategies for the prevention and control of BSF should consider the hypothesis that ticks infected with R. rickettsii can be harbored in human dwellings in peri-urban areas.

"Which Factors Affect Pregnancy Until Calving and Pregnancy Loss in Buffalo Recipients of in vitro Produced Embryos?"

In vitro embryo production and embryo transfer (ET) in buffaloes has been developed for decades. However, most studies are focused on the donor or laboratory improvements, and there is a lack of reports regarding the recipients. Therefore, our aim was to investigate factors associated to pregnancy (P/ET), pregnancy loss (PL), and calving rates in buffalo recipients. The studied factors were season, recipient parity, the synchronization protocol, the CL diameter, asynchrony between the embryo and the recipient, the day of the recipient estrous cycle, the embryo (fresh vs. vitrified), the day of embryo development, and the embryo stage. These retrospective data, from a program of in vitro produced embryos, were analyzed by logistic regression, and the odds ratio was also estimated. Two factors were related to P/ET and the calving rate: (1) progesterone associated to estradiol plus eCG protocol for fixed time ET tended to affect positively P/ET on day 30 (41.9 vs. 36.1%, respectively; P = 0.07; AOR = 1.28) and P/ET on day 60 (37.8 vs. 36.1%, respectively; P = 0.09; AOR = 1.08) compared to the Ovsynch protocol; and (2) the CL diameter (≥14.5 mm) at transfer increased P/ET on day 30 (47.4 vs. 32.5%; P < 0.01; AOR = 1.87) and on day 60 (45.3 vs. 27.7%; P < 0.01; AOR = 2.16), and also the calving rate (37.9 vs. 21.7%; P < 0.01; AOR = 2.20). PL was greater when ET was done in the nonbreeding season compared to the breeding season (PL 30-60: 12.8 vs. 0.0%, P = 0.01; AOR > 999.99; PL 60-calving: 26.8 vs. 3.6%, P = 0.03; AOR = 9.90; and PL 30-calving: 36.2 vs. 3.6%, P = 0.01; AOR = 15.30). In conclusion, the data of our study indicated that the synchronization protocol, the CL diameter, and ET during the breeding season impacted the reproductive efficiency of buffalo recipients.

Genetic material from buffalo and cattle: crucial importance in the formalization of bilateral trade between India and Brazil.

The trade in live animals between India and Brazil dates from the late nineteenth century when European travellers traded animals of Indian origin for display in zoos. Considering the origin of coffee and sugar cane, as well as the expertise related to mineral evaluation, we need to consider that India was involved in important economic cycles of Brazil, even indirectly. This virtuous flow of trade has been maintained and intensified throughout modern history, especially after these two nations gained political independence from their colonisers, thereby becoming independent in mercantile affairs. This paper addresses the main points related to the use of animals of Indian origin in Brazil. We revisit some of the historical aspects of the process of colonisation of Brazil, as well as the importation of animals from India. The restrictions imposed on this process due to the occurrence of diseases in cattle and buffalo in India will be examined. At the end of the text, emphasis will be given to the risks of introducing exotic diseases into Brazil.

Molecular method for the semiquantitative identification of gastrointestinal nematodes in domestic ruminants.

Standard diagnostic methods currently in use for the identification of helminth infections in ruminants are based on the morphological analysis of immature and adult stages of parasites. This paper describes a method for the semiquantitative identification of nematodes, mainly Trichostrongyloidea, at species-level resolution. The method is based on amplification and fragment analysis followed by minisequencing of the ITS-2 region (internal transcribed spacer 2) of the ribosomal DNA of parasite eggs or larvae. This method allows for the identification of seven genera (Chabertia, Cooperia, Haemonchus, Oesophagostomum, Ostertagia, Teladorsagia, and Trichostrongylus) and 12 species (Chabertia ovina, Cooperia curticei, Cooperia punctata, Cooperia oncophora/Cooperia surnabada, Haemonchus contortus, Haemonchus placei, Haemonchus longistipes, Oesophagostomum asperum, Oesophagostomum radiatum, Ostertagia ostertagi, Trichostrongylus axei, and Trichostrongylus colubriformis) of infectious nematodes of domestic ruminants. The concordance between the morphological and molecular analyses in the detection of genera ranged from 0.84 to 0.99, suggesting the proposed detection method is specific, semiquantitative, less laborious, and highly cost-efficient.

Apparent Digestibility of Nutrients, Blood Parameters and Body Development of Dewormed and Not Dewormed Weanlings.

Weanlings undergo rapid body development in the first year of life and, in this period, are more susceptible to helminth infection that can impair their growth. The objective of this study was to compare the apparent digestibility of nutrients, blood parameters, and body development of deworming and not deworming weanlings. Fourteen Mangalarga Marchador weanling colts, on a farm in Northern Minas Gerais, Brazil, were divided into two groups: dewormed (D) and not dewormed (ND) groups. The weanlings were kept separately for 3 months in two pastures of Cynodon nlemfuensis cv. African Star Grass. They also were supplemented with Cynodon dactylon cv. Tifton 85 predried hay ad libitum and 1.5 kg.100 kg-1 of body weight (BW) of corn-based concentrate. Eggs per gram of feces (EPG) of the weanlings were measured monthly. Group D was dewormed (200 mcg.kg-1 BW ivermectin + 2.5 mg.kg-1 BW praziquantel) whenever EPG was ≥500. Group ND weanlings were not treated. The weanlings were subjected to an apparent digestibility assay (total fecal collection procedure). Every month, the weanlings were weighed, evaluated for body condition score, and had withers height, croup height, body length, and thoracic circumference measured. Group ND was infected mainly by small strongyles. There was no difference between groups (P > .05) for morphometric measurements, dry matter intake, and digestibility coefficients, except for apparent digestibility of calcium, which was higher (P < .05) in group D. Small strongyles infection in six- to nine-month-old weanlings fed high grain, nutrient-balanced rations apparently did not affect growth, blood parameters, and apparent digestibility of nutrients.

Design and validation of a 90K SNP genotyping assay for the water buffalo (Bubalus bubalis).

BACKGROUND: The availability of the bovine genome sequence and SNP panels has improved various genomic analyses, from exploring genetic diversity to aiding genetic selection. However, few of the SNP on the bovine chips are polymorphic in buffalo, therefore a panel of single nucleotide DNA markers exclusive for buffalo was necessary for molecular genetic analyses and to develop genomic selection approaches for water buffalo. The creation of a 90K SNP panel for river buffalo and testing in a genome wide association study for milk production is described here. METHODS: The genomes of 73 buffaloes of 4 different breeds were sequenced and aligned against the bovine genome, which facilitated the identification of 22 million of sequence variants among the buffalo genomes. Based on frequencies of variants within and among buffalo breeds, and their distribution across the genome, inferred from the bovine genome sequence, 90,000 putative single nucleotide polymorphisms were selected to create an Axiom® Buffalo Genotyping Array 90K. RESULTS: This 90K "SNP-Chip" was tested in several river buffalo populations and found to have ∼70% high quality and polymorphic SNPs. Of the 90K SNPs about 24K were also found to be polymorphic in swamp buffalo. The SNP chip was used to investigate the structure of buffalo populations, and could distinguish buffalo from different farms. A Genome Wide Association Study identified genomic regions on 5 chromosomes putatively involved in milk production. CONCLUSION: The 90K buffalo SNP chip described here is suitable for the analysis of the genomes of river buffalo breeds, and could be used for genetic diversity studies and potentially as a starting point for genome-assisted selection programmes. This SNP Chip could also be used to analyse swamp buffalo, but many loci are not informative and creation of a revised SNP set specific for swamp buffalo would be advised.

Comparison of McMaster and Mini-FLOTAC fecal egg counting techniques in cattle and horses.

The aim of this study was to compare two fecal egg count (FEC) techniques; McMaster (McM) and Mini-FLOTAC (mF), for the detection of cattle and horse gastrointestinal nematode eggs, in different locations. Experiment 1: feces were collected from 16 cattle and FEC was performed individually, using mF with the sensitivity of 5 eggs per gram of feces (EPG) and McM with a sensitivity of 50 EPG at Empresa de Pesquisa Agropecuária de Minas Gerais - EPAMIG and the Laboratory of Parasitic Diseases of the University of Parana - LDP/UFPR. Experiment 2: Fecal samples from 30 horses were analyzed with mF (sensitivity of 5 EPG) and McM (sensitivity of 25 EPG) at the University of Mato Grosso do Sul - UFMS and LPD/UFPR. Experiment 3: feces were collected from 14 foals and FEC was performed using mF (sensitivity of 5 EPG); and McM (sensitivity of 25 EPG) only at the LPD/UFPR. For cattle, the average FEC of mF was 962 at LPD; and 1248 at EPAMIG; for McM it was 1393 at LPD and 1563 at EPAMIG. For horses, the FEC average using the mF was 650 at LPD and 469 at UFMS; and for McM it was 677 at LPD and 554 at UFMS. For foals, the average FEC for mF was 404 and 436 for McM. In all experiments, the standard deviation and the coefficient of variation values were significantly lower for mF. Therefore, it is recommended the use of the Mini-FLOTAC technique, which is a method with less variability and higher accuracy, particularly for animals with low FEC.

Frequency of benzimidazole resistance in Haemonchus contortus populations isolated from buffalo, goat and sheep herds / Frequência da resistência ao benzimidazol em populações de Haemonchus contortus isoladas de rebanhos de bubalinos, caprinos e ovinos

Anthelmintic resistance is an increasing problem that threatens livestock production worldwide. Understanding of the genetic basis of benzimidazole resistance recently allowed the development of promising molecular diagnostic tools. In this study, isolates of Haemonchus contortus obtained from goats, sheep and buffaloes raised in Brazil were screened for presence of the polymorphism Phe200Tyr in the β-tubulin 1 gene, which confers resistance to benzimidazole. The allelic frequency of the mutation conferring resistance ranged from 7% to 43%, and indicated that resistance to benzimidazole could be found in nematodes isolated from all the ruminant species surveyed. Although significant variation in the frequency of the F200Y mutation was observed between different herds or host species, no significant variation could be found in populations isolated from animals within the same herd. These findings suggest that screening of samples from a few animals has the potential to provide information about the benzimidazole resistance status of the entire herd, which would enable a considerable reduction in the costs of diagnosis for the producer. Molecular diagnosis has practical advantages, since it can guide the choice of anthelmintic drug that will be used, before its application in the herd, thus reducing the economic losses driven by anthelmintic resistance.

A resistência aos anti-helmínticos é um problema crescente que ameaça a produção pecuária em todo o mundo. A compreensão da base genética da resistência ao benzimidazol permitiu, recentemente, o desenvolvimento de métodos diagnósticos moleculares promissores. Neste estudo, isolados de Haemonchus contortus obtidos a partir de rebanhos de caprinos, ovinos e bubalinos criados no Brasil foram avaliados quanto à presença do polimorfismo F200Y no gene da β-tubulina1, o qual confere resistência ao benzimidazol. A frequência alélica da mutação variou de 7% a 43%, indicando que a resistência ao benzimidazol pode ser encontrada em nematoides isolados a partir de todas as espécies de ruminantes pesquisadas. Embora tenha sido observada variação significativa das frequências de mutação F200Y entre rebanhos/espécies hospedeiros distintos, não foi encontrada variação significativa entre populações isoladas de animais dentro de um mesmo rebanho. Estes achados sugerem que a avaliação de amostras de alguns poucos animais tem o potencial de fornecer informações sobre o nível de resistência ao benzimidazol de todo o rebanho, possibilitando uma redução considerável dos custos de diagnóstico para o produtor. O diagnóstico molecular apresenta vantagens práticas, uma vez que pode guiar a escolha da base anti-helmíntica a ser utilizada antes da sua aplicação no rebanho, reduzindo, portanto, as perdas ocasionadas pela resistência aos fármacos anti-helmínticos.

The efficacy and safety of alphacypermethrin as a pour-on treatment for water buffalo (Bubalus bubalis) infested with Haematopinus tuberculatus (Phthiraptera: Haematopinidae).

The sucking louse Haematopinus tuberculatus (Burmeister 1839) is an ectoparasite of buffaloes, cattle, camels, and American bison. Alphacypermethrin (ACYP) is a pyrethroid insecticide commonly used to control arthropods of veterinary and public health interest. Therapeutics, such as antiparasitic compounds, is often administered to buffaloes based on dosage and intervals recommended for cattle because very few drugs have buffalo-specific label indications. A trial was conducted on 20 louse-infested buffaloes at a farm to assess the efficacy and safety of ACYP pour-on, at the manufacturer's recommended dose for cattle, on buffaloes naturally infested by H. tuberculatus. Ten animals were assigned to ACYP-treated group (ACYP-group) and ten to untreated control group (C-group). On day 0, all ACYP-group buffaloes received alphacypermethrin pour-on. Louse counts were performed on days -1, 7, 14, 21, 28, 35, 42, 49, and 56 at eight predilection sites on the skin of each buffalo. ACYP was completely effective (100%) at day 7, highly effective (99.8%) at day 14, and completely effective (100%) from day 21 until the end of the study (day 56 post-treatment). During the trial, ACYP was well tolerated by all animals as there were no observed clinically adverse reactions. The results of this trial suggest that ACYP is an effective, safe, and user-friendly compound suitable for treatment of buffaloes with natural louse infestations.

Frequency of benzimidazole resistance in Haemonchus contortus populations isolated from buffalo, goat and sheep herds.

Anthelmintic resistance is an increasing problem that threatens livestock production worldwide. Understanding of the genetic basis of benzimidazole resistance recently allowed the development of promising molecular diagnostic tools. In this study, isolates of Haemonchus contortus obtained from goats, sheep and buffaloes raised in Brazil were screened for presence of the polymorphism Phe200Tyr in the ß-tubulin 1 gene, which confers resistance to benzimidazole. The allelic frequency of the mutation conferring resistance ranged from 7% to 43%, and indicated that resistance to benzimidazole could be found in nematodes isolated from all the ruminant species surveyed. Although significant variation in the frequency of the F200Y mutation was observed between different herds or host species, no significant variation could be found in populations isolated from animals within the same herd. These findings suggest that screening of samples from a few animals has the potential to provide information about the benzimidazole resistance status of the entire herd, which would enable a considerable reduction in the costs of diagnosis for the producer. Molecular diagnosis has practical advantages, since it can guide the choice of anthelmintic drug that will be used, before its application in the herd, thus reducing the economic losses driven by anthelmintic resistance.

Genetic diversity patterns of Haemonchus placei and Haemonchus contortus populations isolated from domestic ruminants in Brazil.

Parasitic nematodes of the genus Haemonchus infect a range of ruminant hosts and are of major veterinary and economic importance. In this study, the genetic variability of seven isolates of Haemonchus placei and Haemonchus contortus was evaluated using the mitochondrial gene cytochrome oxidase subunit I and the nuclear gene b-tubulin isotype 1. A total of 156 specimens were obtained from cattle, sheep, goat and buffalo herds raised on commercial properties from the southern and southeastern regions of Brazil and identified to the species level by sequencing of the nuclear internal transcribed spacer 2. Thirty-four percent of the specimens were identified as H. placei and 66% as H. contortus. Cattle were the preferred hosts for H. placei, whereas H. contortus was most frequent in the other three ruminant species. Analysis of genetic differentiation between isolates revealed that high rates of gene flow are operating among populations of both nematode species, including among those from different ruminant host species. Populations of H. placei were less polymorphic and presented a lower frequency of single nucleotide polymorphisms associated with benzimidazole resistance compared with H. contortus. In line with the low amount of genetic structure observed among isolates, alleles of b-tubulin 1 associated with benzimidazole resistance were present at relatively high frequencies of 5­20% in isolates of H. contortus from farms that never used this class of anthelmintic. The results presented here are consistent with the hypothesis of multiple origins of alleles associated with benzimidazole resistance, with the trade of animals among properties acting as the main factor promoting the spread of anthelmintic resistance.

Hemogram of buffaloes (bubalus bubalis) wormed and nonwormed by helminthes

The gastrointestinal parasitoses of domestic animals have a great impact on the hematological status but nonethelessresearch on this subject concerning buffaloes is rare. Thus, the blood profile of buffalo calves naturally infected by parasitesfrom the seventh to the 300th day of life. Animals were distributed in three experimental groups treated with ivermectin,fenbendazole, and placebo, respectively. Changes of hematological parameters were related to the presence of adultgastrointestinal nematodes, which were diagnosed and identified by the presence of eggs in the feces of wormed animals ascompared to those medicated.

Effects of urea on the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

This study aimed at evaluating the effects of urea on Rhipicephalus (Boophilus) microplus. The experiment was divided into two stages. In Stage I, Brachiaria brizantha was placed into 30 pots, each with an area of 18 cm(2).These were divided into three groups of ten pots each: G1 non-treated control group, G2 treated with 15 g of urea per pot and G3 treated with 15 g of urea+10% of ammonium sulphate. Three engorged female ticks were placed in each pot and then 1.8l of water were added. In the second stage, a control group was maintained without the addition of urea and another group was treated with urea, each group comprising ten Mombaça grass (Panicum maximum cv. Mombaça) beds. On day zero, 12 engorged females were placed in each grass bed where were then fertilized with 60 g of urea per bed, only in the grass beds of the treated group. On the 27th day, the grass was cut in beds 1-5 in both groups and beds 1-5 in the treated group were fertilized a second time. On the 40th day, pieces of white flannel measuring 1.60 m × 1.00 m were spread over the grass to check for larvae presence. In stage I, observations conducted 24h after contact with urea showed a 100% death rate among the engorged females in G2; in group 3, only one engorged female still remained alive. In stage II, the counting of larvae reported 85.97% (P<0.0001) fewer parasites in the treated group compared to the control group.

Possible acquired resistance of dogs successively infested by Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) nymphs.

The present study aimed to evaluate the occurrence of immune resistance in dogs successively infested with Amblyomma cajennense nymphs. Five animals were submitted to four consecutive infestations with A. cajennense nymphs, at fourteen-day intervals. For each infestation, 50 nymphs were used per animal and data on the parasitic and non-parasitic periods were recorded. The average recovering rate of engorged nymphs in the successive infestations were 52.0, 29.2, 9.6 and 12.8%, respectively, with a significant reduction (p<0.05) of this parameter from the second infestation onwards. The modal drop-off day of engorged nymphs was Day 4 of parasitism in all infestations. The average mortality rates of nymphs seen on the first, second, third and fourth infestations were 3.6, 3.2, 2.0 and 2.8%, respectively, with no significant differences among them (p<0.05). In addition, no significant differences were seen among the ecdysis rates for specimens recovered from successive parasitic challenges. The study results suggest that the acquired resistance of infested dogs had a negative effect on recovery rate of A. cajennense nymphs; however, it did not affect the other biological parameters evaluated.

Possible acquired resistance of dogs successively infested by Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) nymphs / Possibilidade de ocorrência de resistência adquirida em cães sucessivamente infestados por ninfas de Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)

The present study aimed to evaluate the occurrence of immune resistance in dogs successively infested with Amblyomma cajennense nymphs. Five animals were submitted to four consecutive infestations with A. cajennense nymphs, at fourteen-day intervals. For each infestation, 50 nymphs were used per animal and data on the parasitic and non-parasitic periods were recorded. The average recovering rate of engorged nymphs in the successive infestations were 52.0, 29.2, 9.6 and 12.8%, respectively, with a significant reduction (p < 0.05) of this parameter from the second infestation onwards. The modal drop-off day of engorged nymphs was Day 4 of parasitism in all infestations. The average mortality rates of nymphs seen on the first, second, third and fourth infestations were 3.6, 3.2, 2.0 and 2.8%, respectively, with no significant differences among them (p < 0.05). In addition, no significant differences were seen among the ecdysis rates for specimens recovered from successive parasitic challenges. The study results suggest that the acquired resistance of infested dogs had a negative effect on recovery rate of A. cajennense nymphs; however, it did not affect the other biological parameters evaluated.

O presente trabalho teve por objetivo avaliar a ocorrência de resistência imune em cães, frente a infestações sucessivas por ninfas de Amblyomma cajennense. Para tanto, cinco animais foram submetidos a quatro infestações consecutivas por ninfas de A. cajennense em intervalos de quatorze dias. Foram aplicadas 50 ninfas em cada animal por infestação e os dados referentes aos períodos parasitários e não parasitários, foram registrados. As taxas médias de recuperação de ninfas ingurgitadas, verificadas nas sucessivas infestações foram de 52,0, 29,2, 9,6 e 12,8%, sendo observada uma redução significativa (p < 0,05) nesse parâmetro a partir da segunda infestação. O dia modal de queda das ninfas ingurgitadas em todas as infestações foi o 4º dia de parasitimo. As taxas médias de mortalidade de ninfas observadas no primeiro, segundo, terceiro e quarto desafio parasitário foram de, respectivamente, 3,6, 3,2, 2,0 e 2,8%, não havendo diferença significativa entre elas (p < 0,05). Não observou-se diferença significativa (p < 0,05) entre as taxas de ecdise reportadas para os exemplares recuperados nos sucessivos desafios parasitários. Esses resultados sugerem que a resistência adquirida nos cães parasitados afetou negativamente a taxa de recuperação das ninfas de A. cajennense inoculadas nesses animais, contudo não apresentou nenhum efeito sobre os demais parâmetros biológicos avaliados.

An outbreak of malignant catarrhal fever in Murrah buffaloes in Minas Gerais, Brazil / Surto de febre catarral maligna (FCM) em búfalos da raça Murrah no estado de Minas Gerais

An outbreak of Malignant Catarrhal Fever (MCF) resulted in death of five female buffaloes and one domestic cow from the same farm. Four buffaloes died 10-15 days after the appearance of clinical signs, while the fifth was euthanized in extremis, after similar clinical signs. Histopathological lesions included multifocal histiolymphocytic epicarditis, myocarditis and lymphocytic interstitial pneumonia, which are commonly seen in cases of MCF in buffaloes. Furthermore, lymphocytic vasculitis centered in the adventitia, with occasional fibrinoid necrosis in the muscular layer, was found in the kidneys, liver, spleen, lymph nodes and brain. Nucleotide sequencing of DNA fragments from the central nervous system amplified by PCR revealed 98 percent similarity with known OHV-2 sequences from Genbank. Additionally, PCR analysis also revealed the presence of OHV-2 DNA in the peripheral mononuclear blood cells of two clinically healthy buffaloes. The diagnosis of MCFwas based on epidemiological, clinical, gross and histopathological findings and on the results of a semi-nested PCR followed by nucleotide sequencing.

É relatado um surto de febre catarral maligna (FCM) em Minas Gerais, que resultou na morte de 5 búfalas e uma vaca de uma mesma propriedade. Quatro búfalas morreram com 10-15 dias após o início dos sinais clínicos e uma búfala foi sacrificada in extremis, após manifestar sinais clínicos semelhantes. O exame histopatológico revelou lesões comumente observadas em búfalos com FCM como epicardite e miocardite histiolinfocítica multifocal e pneumonia linfocítica intersticial. Além disso, vasculite linfocítica, principalmente na camada adventícia, com necrose fibrinóide da camada muscular, foi observada no rim, fígado, baço, linfonodos e cérebro. A seqüência de nucleotídeos amplificada pela técnica de PCR revelou 98 por cento de homologia entre o fragmento de DNA amplificado da amostra do sistema nervoso central (SNC) da búfala com seqüências de OHV-2 previamente depositadas no Genbank. Adicionalmente, a técnica de PCR revelou a presença do DNA viral no sangue total de 2 búfalas, clinicamente sadias. O diagnóstico de FCM foi baseado em dados epidemiológicos, clínicos, patológicos, histopatológicos e semi-nested PCR.

Possible acquired resistance of dogs successively infested by Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae) nymphs

The present study aimed to evaluate the occurrence of immune resistance in dogs successively infested with Amblyomma cajennense nymphs. Five animals were submitted to four consecutive infestations with A. cajennense nymphs, at fourteen-day intervals. For each infestation, 50 nymphs were used per animal and data on the parasitic and non-parasitic periods were recorded. The average recovering rate of engorged nymphs in the successive infestations were 52.0, 29.2, 9.6 and 12.8%, respectively, with a significant reduction (p 0.05) of this parameter from the second infestation onwards. The modal drop-off day of engorged nymphs was Day 4 of parasitism in all infestations. The average mortality rates of nymphs seen on the first, second, third and fourth infestations were 3.6, 3.2, 2.0 and 2.8%, respectively, with no significant differences among them (p 0.05). In addition, no significant differences were seen among the ecdysis rates for specimens recovered from successive parasitic challenges. The study results suggest that the acquired resistance of infested dogs had a negative effect on recovery rate of A. cajennense nymphs; however, it did not affect the other biological parameters evaluated.

O presente trabalho teve por objetivo avaliar a ocorrência de resistência imune em cães, frente a infestações sucessivas por ninfas de Amblyomma cajennense. Para tanto, cinco animais foram submetidos a quatro infestações consecutivas por ninfas de A. cajennense em intervalos de quatorze dias. Foram aplicadas 50 ninfas em cada animal por infestação e os dados referentes aos períodos parasitários e não parasitários, foram registrados. As taxas médias de recuperação de ninfas ingurgitadas, verificadas nas sucessivas infestações foram de 52,0, 29,2, 9,6 e 12,8%, sendo observada uma redução significativa (p 0,05) nesse parâmetro a partir da segunda infestação. O dia modal de queda das ninfas ingurgitadas em todas as infestações foi o 4º dia de parasitimo. As taxas médias de mortalidade de ninfas observadas no primeiro, segundo, terceiro e quarto desafio parasitário foram de, respectivamente, 3,6, 3,2, 2,0 e 2,8%, não havendo diferença significativa entre elas (p 0,05). Não observou-se diferença significativa (p 0,05) entre as taxas de ecdise reportadas para os exemplares recuperados nos sucessivos desafios parasitários. Esses resultados sugerem que a resistência adquirida nos cães parasitados afetou negativamente a taxa de recuperação das ninfas de A. cajennense inoculadas nesses animais, contudo não apresentou nenhum efeito sobre os demais parâmetros biológicos avaliados.

[Control of Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) on equines]. / Controle de Anocentor nitens (Neumann, 1897) (Acari: Ixodidae) em equinos.

This trial evaluated control practices of Anocentor nitens on equines, using spraying devices and application of acaricide paste formulation in the auricular pavilion and nasal diverticulum. The study was carried out from October 2003 to March of 2008 and the evaluations had been divided in the following stages: Phase 1--out/03 mar/04 and Phases 2, 3, 4 and 5, respectively, correspondents to the month's periods until março/08. It was used score of 0 to 3 to classify infestation levels. From abr/04 to mar/06 was implanted a schedule of acaricide sprayings every seven days and divided in two series. The first one beginning in April 2004 and the second beginning in July, both using six sprayings treatments with pyrethroid chemical base--cypermethrin 0,015%, plus topical treatments applied monthly in the auricular pavilions (powder acaricide). From abril/06 to março/08 was carried out similar schedule treatments, each two months, using an experimental acaricide paste in the auricular pavilion and nasal diverticulum. Phases 2 and 3 did not showed reduction of the parasitic loads of A. nitens compared to the control period. Whereas in Phases 4 and 5 registered significant reduction compared control period and also with the results of Phases 2 and 3, characterizing the effectiveness of the treatment with the acaricide paste formulation. Results demonstrated of A. nitens populations present in the nasal diverticulum are important in the maintenance of the infestations on equines, and necessary attention to this anatomical structure when controlling ticks.

[Effect of the urea fertilization in pasture on Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)]. / Efeito da adubação com uréia em pastagem, sobre Rhipicephalus(Boophilus) microplus (Acari: Ixodidae).

The objective of this study was to verify the effect of the urea fertilization in pasture on Rhipicephalus (Boophilus) microplus population in free living stage. Two groups had been made, a control group and a urea treatment group, each group with 10 lots of Mombaça grass (Panicum maximum cv. Mombaça). In day zero had been placed 12 engorged tick females in each lot and made fertilization with urea in the dosage of 60 g in the lots of the treat group. In 27th day the grass was cutted out in 1 to 5 lots of both groups and fertilized with urea in the lots of 1 to 5 in the treat group. In 40th day was released a white flannel 1.60 x 1.00 m length on each lot to verify the presence of larvae. The results presented a difference of 85.97% (P < 0.0001) between the treat group and the control group.

[First notification of Eimeria bareillyi (Apicomplexa: Eimeridae) in feces of buffalo calves (Bubalus bubalis) naturally infected in Minas Gerais, Brazil]. / Primeiro diagnóstico de Eimeria bareillyi (Apicomplexa: Eimeridae) nas fezes de bezerros bubalinos (Bubalus bubalis) naturalmente infectados no estado de Minas Gerais, Brasil.

In this study the evolution of Eimeriosis in naturally infected calves was analyzed during 23 days starting at birth. The specie E. bareillyi was first identified in feces culture. Later other species of Eimeria already described in water buffalo were identified. The animals which died were submitted to necropsy, revealing macroscopic lesions in the ileum region. Histological analyses of the ileum region showed acute necrotic enteritis and the presence of Eimeria sp. in different developmental stages. Early infection by this parasite could be responsible for a secondary bacterial infection trough the intestinal lesions. The utilization of prophylactic medication and the therapeutic treatment of clinical Coccidiosis in water buffalo calves are necessary to their satisfactory development and surveillance.