Resistance to deltamethrin, fipronil and ivermectin in the brown dog tick, Rhipicephalus sanguineus sensu stricto, Latreille (Acari: Ixodidae).

Rhipicephalus sanguineus sensu stricto (s.s.), the temperate lineage of the brown dog tick, is the most common tick found on dogs from urban areas in Rio Grande do Sul (RS) state, southern Brazil. Chemical treatments against ticks are important to control this pest, but can lead to selection for acaricide resistance. Unfortunately, little is known about acaricide resistance in this tick species in Brazil, although such information is very important to companion animal clinical practice. The objective of this study was to analyze acaricide susceptibility of R. sanguineus s.s. from the metropolitan area of Porto Alegre, RS. Engorged females ticks were collected in ten different locations, from naturally infested dogs or the environment (homes, shelters and kennels). The progenies were used in toxicological larval tests with deltamethrin, fipronil and ivermectin. Mortality data was used to determine the median lethal concentrations (LC50) for each tick population and resistance was characterized based on relative susceptibility of the different tick populations against each acaricide. Seven samples were considered resistant to deltamethrin, with resistance ratios (RR) ranging from 2.32 to 5.67. From five tick populations tested with fipronil, three were considered resistant, with RR varying from 2.56 to 13.83. For ivermectin, resistance ratios were lower, ranging from 1.54 to 2.97. The results reveal a notable variance of susceptibility to deltamethrin, fipronil and ivermectin in the R. sanguineus s.s. populations studied. This study documents for the first time the existence of acaricide-resistant populations of R. sanguineus s.s. in Brazil.

Cholinesterases as markers of the inflammatory process associated oxidative stress in cattle infected by Babesia bigemina.

The objective of this study was to assess the influence of an asymptomatic experimental infection by Babesia bigemina on cholinesterase's as markers of the inflammatory process and biomarkers of oxidative imbalance. For this purpose, eight naive animals were used, as follows: four as controls or uninfected; and four infected with an attenuated strain of B. bigemina. Blood samples were collected on days 0, 7 and 11 post-inoculation (PI). Parasitemia was determined by blood smear evaluation, showing that the infection by B. bigemina resulted in mean 0.725 and 0.025% on day 7 and 11 PI, respectively, as well as mild anemia. The activities of acetylcholinesterase, butyrylcholinesterase and catalase were lower, while levels of thiobarbituric acid reactive substances and superoxide dismutase activity were higher in infected animals, when compared with the control group. This attenuated strain of B. bigemina induced an oxidative stress condition, as well as it reduces the cholinesterasés activity in infected and asymptomatic cattle. Therefore, this decrease of cholinesterase in infection by B. bigemina purpose is to inhibit inflammation, for thereby increasing acetylcholine levels, potent anti-inflammatory molecules.

Imidocarb dipropionate in the treatment of Anaplasma marginale in cattle: Effects on enzymes of the antioxidant, cholinergic, and adenosinergic systems.

Anaplasmosis is a worldwide hemolytic disease in cattle caused by a gram-negative obligatory intracellular bacterium, characterized by anemia and jaundice. Among the treatments used for anaplasmosis is a drug called imidocarb dipropionate, also indicated as an immunomodulator agent. However, it causes side effects associated with increased levels of acetylcholine. In view of this, the effects of imidocarb dipropionate on the purinergic system, and antioxidant enzymes in animals naturally infected by Anaplasma marginale were evaluated. Young cattle (n = 22) infected by A. marginale were divided into two groups: the Group A consisted of 11 animals used as controls; and the Group B composed of 11 animals. Imidocarb dipropionate (5 mg/kg) was used subcutaneously to treat both groups (the Group A on day 6 and the Group B on day 0). The treatment reduced acetylcholinesterase (AChE), and adenosine deaminase (ADA) activities, and increased the dismutase superoxide and catalase activities. No changes on lipid peroxidation (TBARS levels) and BChE activities were noticed. These results suggest that imidocarb dipropionate used to treat A. marginale infection in cattle has effect on antioxidant enzymes, and significantly inhibits the enzymatic activities of ADA and AChE.

Cattle experimentally infected by Anaplasma marginale: Influence of splenectomy on disease pathogenesis, oxidative profile, and antioxidant status.

Bovine anaplasmosis is caused by the obligate intraerythrocytic bacteria Anaplasma marginale. These bacteria are transmitted by tick species such as Rhipicephalus (Boophilus) microplus, blood-sucking insects, and fomites (needles, clippers, and other blood contaminated equipment). During the acute phase of infection, animals may develop fever, anemia, jaundice, and hepatosplenomegaly. The aims of this study are to quantify the bacteremia by quantitative PCR in eight naïve calves experimentally infected by A. marginale [splenectomized (n = 4), and intact/non-splenectomized (n = 4)], and to correlate these findings with markers of oxidative stress on days 0, 8, 15, 21 and 23 post-infection. Complete blood counts (CBC) were performed in both groups. Lipid peroxidation was estimated by quantifying thiobarbituric acid reactive substances (TBARS); and non-enzymatic antioxidants were assessed by erythrocyte content of non-protein thiols (NPSH). There were no significant differences in complete blood counts (CBC) between the two groups. However, both groups had a slight decrease on packet cell volume (PCV), erythrocytes and hemoglobin concentration, as well as an increase in total leukocyte counts due to elevated lymphocytes when comparing pre and post-infection with A. marginale. Progressive increase on TBARS levels and concomitant decrease on NPSH content were observed in all animals, without significant differences between splenectomized and intact animals. A positive correlation between bacteremia and TBARS, and a negative correlation between bacteremia and NPSH were observed in both groups with higher correlation for NPSH in splenectomized animals. A negative correlation between TBARS and NPSH levels was observed in both groups indicating lipid peroxidation without a non-enzymatic antioxidant response. The results of experimental infection by A. marginale in cattle showed that bacteremia has an impact on lipid peroxidation regardless of the splenectomy.

Influence of experimental Anaplasma marginale infection and splenectomy on NTPDase and 5'nucleotidase activities in platelets of cattle.

The objective of this paper was to evaluate NTPDase and 5'-nucleotidase activities in platelets of bovine with and without spleen and infected by Anaplasma marginale. Our results demonstrate that infection along with splenectomy is able of inducing a profile of cellular protection, which showed an increase in the degradation of the nucleotides ATP and ADP by NTPDase, in addition to AMP by 5'nucleotidase to form the nucleoside adenosine in platelets, i.e., the enzymatic activities of platelets were increased in splenectomized animals when compared to non-splenectomized group. It notes that adenosine is a molecule with anti-inflammatory function. But this profile is related to a deficiency in immune signaling triggered by nucleotide ATP, which may be related to the increase in bacteremia and disability in combating the parasite in splenectomized host.

Diminazene aceturate liposomes: morphometric and biochemical liver, kidney, and spleen of rats infected with Trypanosoma evansi.

The aim of this study was to evaluate the effect of treatment with liposomal (L-DMZ) and conventional (C-DMZ) diminazene aceturate formulations on hepatic and renal functions of rats, experimentally infected with Trypanosoma evansi. For this purpose, 72 Wistar rats (Rattus norvegicus) were divided into six groups (A, B, C, D, E, and F). Each group was subdivided into two other subgroups in order to assess the biochemical and histological results on days 7 and 40 post-treatment (PT). Treatments were carried out based on two different therapeutic protocols: L-DMZ and C-DMZ at 3.5mg/kg(-1), single dose (groups C and D), and five successive doses within intervals of 24h (groups E and F). Groups A and B corresponded to uninfected and infected (without treatment) animals, respectively. Sample collections were held on days 7 and 40 PT for the assessment of hepatic [alkaline phosphatase (AP), alanine transferase (ALT), albumin, gamma glutamil transferase (GGT) and renal functions (creatinine and urea). Additionally, the histology of fragments of liver, kidney, and spleen was performed. Animals in group B showed a significant increase in AP, GGT, ALT, and urea when compared with group A. On day 7 post-inoculation (PI), the biochemical analysis showed a reduction (P<0.05) of AP and GGT, while the levels of urea were increased in groups C, D, E, F. On day 40 PT, ALT was increased in these same groups when compared with group A. In histopathology, changes in liver samples were observed on day 7 PT in groups D and F, especially regarding the area and density of the hepatocytes. Renal analysis exhibited changes in glomerular space, glomerular, and corpuscular areas in group E. Therefore, these results allowed us to conclude that the treatment with L-DMZ and C-DMZ led to variable biochemical changes, which defined the functions of the liver and kidneys of treated animals, since the main histopathology alterations were observed in animals treated with liposomes, at their higher dosages. Thus, treatments with L-DMZ and C-DMZ in five consecutive doses were effective although being followed by liver toxicity.

Ticks (Acari: Ixodidae) from yellow armadillo, Euphractus sexcinctus (Cingulata: Dasypodidae), in Brazil's Pantanal wetlands.

Tick species parasitizing yellow armadillo, Euphractus sexcinctus, were recorded from October 2006 to October 2007 in Pantanal. A total of 89 ticks were collected from 23 yellow armadillos. Most ticks (n=50) were identified as Amblyomma cajennense (Fabricius) (32 males and 18 females). The only other species found was Amblyomma parvum (Aragão) (three females and two males). The remaining ticks were immatures of Amblyomma (29 nymphs and five larvae). The prevalence of A. cajennense was 55%, the mean intensity was 2.7±0.5 (SE) (n=17) and the mean abundance was 1.5±0.4 (n=31).

Ticks (Acari: Ixodidae) from yellow armadillo, Euphractus sexcinctus (Cingulata: Dasypodidae), in Brazil's Pantanal wetlands

Tick species parasitizing yellow armadillo, Euphractus sexcinctus, were recorded from October 2006 to October 2007 in Pantanal. A total of 89 ticks were collected from 23 yellow armadillos. Most ticks (n = 50) were identified as Amblyomma cajennense (Fabricius) (32 males and 18 females). The only other species found was Amblyomma parvum (Aragão) (three females and two males). The remaining ticks were immatures of Amblyomma (29 nymphs and five larvae). The prevalence of A. cajennense was 55 percent, the mean intensity was 2.7 ± 0.5 (SE) (n = 17) and the mean abundance was 1.5 ± 0.4 (n = 31).

Tripanosomatides like Trypanosoma theileri in the cattle tick Boophilus microplus.

Findings of epimastigotes forms of a tripanosomatide is reported in the hemolymph of the cattle tick Boophilus microplus in the state of Rio Grande do Sul, southern Brazil. Morphological evidences suggest they are similar to Trypanosoma theileri, a species described as non pathogenic to cattle, and usually transmitted by tabanids.

Tripanosomatides like Trypanosoma theileri in the cattle tick Boophilus microplus / Tripanosomatídeos similares a Trypanosoma theileri no carrapato dos bovinos Boophilus microplus

Findings of epimastigotes forms of a tripanosomatide is reported in the hemolymph of the cattle tick Boophilus microplus in the state of Rio Grande do Sul, southern Brazil. Morphological evidences suggest they are similar to Trypanosoma theileri, a species described as non pathogenic to cattle, and usually transmitted by tabanids.

Descreve-se a ocorrência de formas epimastigotas de um tripanosomatideo na hemolinfa do carrapato do bovino Boophilus microplus no Estado do Rio Grande do Sul. Evidências morfológicas sugerem tratar-se de Trypanosoma theileri , espécie descrita como não patogênica aos bovinos e que usualmente é transmitida por tabanídeos.

[Haemaphysalis juxtakochi Cooley, 1946 (Acari: Ixodidae) parasitizing Mazama nana (Hensel, 1872) (Artiodactyla: Cervidae) in the State of Rio Grande do Sul]. / Haemaphysalis juxtakochi Cooley, 1946 (Acari: Ixodidae) parasitando Mazama nana (Hensel, 1872) (Artiodactyla: Cervidae) no Estado do Rio Grande do Sul.

The record of Haemaphysalis juxtakochi Cooley, an ixodid tick, on the brocket deer, Mazama nana (Hensel), represents a new report after 34 years of its last report in the State of Rio Grande do Sul. The tick specimens (three males and one female) were found in Cachoeira do Sul, RS (30 degrees 02'21''S, 52 degrees 53'38''W). This place is elevated 72 m sea above, with an annual average temperature of 18.8 degrees C, and annual average rainfall of 1.438 mm. This is the first record of this tick species in a Cervidae and it is the second occurrence report for the State of Rio Grande do Sul.

Primeiro relato de Amblyomma fuscum Neumann, 1907 (acari: ixodidae) parasitando lagarto da espécie Tupinambis teguixin (L.), no município de Glorinha, estado do Rio Grande do Sul, Brasil / The first report of Amblyomma fuscum Neumann, 1907 (acari ixodidae) on the lizard Tupinambis teguixin (L.) at the municipality of Glorinha, state of Rio Grande do Sul, Brazil

Amblyomma fuscum conhecida somente no Brasil, tem sido descrita como uma espécie rara de carrapato com relatos de sua ocorrência nas regiões sul e sudeste. Este é um novo registro desta espécie (9 fêmeas) parasitando lagarto (Tupinambis teguixin), no Município de Glorinha, Estado do Rio Grande do Sul. As fêmeas foram depositadas na coleção do Instituto de Pesquisas Veterinárias Desidério Finamor (7 espécimes) e na coleção de Acari do Instituto Butantan, Estado de São Paulo (2 espécimes). O achado confirma o estabelecimento de A. fuscum no Sul do Brasil.

Amblyomma fuscum known only from Brazil has been described as a rare tick species with few reports of its occurrence in South and Southeast region. This is a new records this tick species (9 females) parasitizing lizard (Tupinambis teguixin) at the Municipality of Glorinha, State of Rio Grande do Sul. The females were deposited in the tick collection of Veterinary Research Institute Desiderio Finamor (7 specimens), Eldorado do Sul, RS and in the Acari collection from Instituto Butantan, São Paulo, State of São Paulo (2 specimens). The finding confirms establishment de A. fuscum in the South of Brazil.

Haemaphysalis juxtakochi Cooley, 1946 (Acari: Ixodidae) parasitando Mazama nana (Hensel, 1872) (Artiodactyla: Cervidae) no estado do Rio Grande do Sul / Haemaphysalis juxtakochi Cooley, 1946 (Acari: Ixodidae) parasitizing Mazama nana (Hensel, 1872) (Artiodactyla: Cervidae) in the State of Rio Grande do Sul

O encontro de Haemaphysalis juxtakochi Cooley, um carrapato ixodídeo, no veado bororó-do-sul, Mazama nana (Hensel), representa novo relato de ocorrência, após 34 anos de seu registro no Estado do Rio Grande do Sul. Os exemplares de carrapatos (3 machos e 1 fêmea) foram encontrados em Cachoeira do Sul, RS (30º02’21"S, 52º53’38"W). O local está a 72 m acima do nível do mar, com uma média anual de temperatura de 18,8°C, e uma precipitação média anual de 1.438 mm. Este é o primeiro registro de H. juxtakochi nesta espécie de cervídeo e um segundo relato de ocorrência para o Estado do Rio Grande do Sul.

The record of Haemaphysalis juxtakochi Cooley, an ixodid tick, on the brocket deer, Mazama nana (Hensel), represents a new report after 34 years of its last report in the State of Rio Grande do Sul. The tick specimens (three males and one female) were found in Cachoeira do Sul, RS (30º02’21"S, 52º53’38"W). This place is elevated 72 m sea above, with an annual average temperature of 18.8°C, and annual average rainfall of 1.438 mm. This is the first record of this tick species in a Cervidae and it is the second occurrence report for the State of Rio Grande do Sul.

[The first report of Amblyomma fuscum Neumann, 1907 (Acari Ixodidae) on the lizard Tupinambis teguixin (L.) at the Municipality of Glorinha, State of Rio Grande do Sul, Brazil]. / Primerio relato de Amblyomma fuscum Neumann, 1907 (Acari Ixodidae) parasitando lagarto da espécie Tupinambis teguixin (L.), no município de Glorinha, Estado do Rio Grande do Sul, Brasil.

Amblyomma fuscum known only from Brazil has been described as a rare tick species with few reports of its occurrence in South and Southeast region. This is a new records this tick species (9 females) parasitizing lizard (Tupinambis teguixin) at the Municipality of Glorinha, State of Rio Grande do Sul. The females were deposited in the tick collection of Veterinary Research Institute Desiderio Finamor (7 specimens), Eldorado do Sul, RS and in the Acari collection from Instituto Butantan, São Paulo, State of São Paulo (2 specimens). The finding confirms establishment de A. fuscum in the South of Brazil.

First record of Amblyomma aureolatum (Pallas, 1772) (Acari: Ixodidae) parasitizing Alouatta guariba (Humboldt) (Primata: Atelidae) in southern Brazil.

A female of Amblyomma aureolatum was found on the howler monkey Alouatta guariba, in Cachoeira do Sul, Rio Grande do Sul, Southern Brazil. This is the first record of this tick species parasitizing this primate species in Brazil.