Vector Of Babesiosis Research Articles

Acaricidal activity of the plant sesquiterpenoids α-costic acid and inuloxin A against the cattle ectoparasitic tick, Rhipicephalus (Boophilus) annulatus

ABSTRACT The obligate ectoparasite Rhipicephalus (Boophilus) annulatus, also known as cattle tick, is the hard tick vector of babesiosis, a protozoal infection that causes severe meat production losses at huge economic costs. Although babesiosis was eradicated from the United States, its vector still exists in Mexico and different security measures are used to prevent its reintroduction into the U.S. Furthermore, the massive use of chemical acaricides during the last century has resulted in the development of resistance and toxicological problems. A possible and more sustainable alternative could be represented by the applications of biopesticides. Recently, two sesquiterpenoids, inuloxin A and α-costic acid isolated from Dittrichia viscosa, a perennial native plant of the Mediterranean basin, showed several interesting biological activities including acaricidal and antifeedant activities. Both inuloxin A and α-costic acid caused an impact on the hatch rate of the eggs and a larval mortality rate higher than 80% in vitro bioassays on eggs of R. annulatus. Moreover, the hatch rate of the eggs and the mortality rate of the larvae seem to be dependent on the timing of application of the compounds on the eggs. These results suggested a potential use of both compounds to control R. annulatus.

Distribution of the tick Dermacentor reticulatus in the United Kingdom.

The recent implication of Dermacentor reticulatus (Ixodida: Ixodidae) in the transmission of canine babesiosis in the U.K. has highlighted the lack of accurate published data on its distribution in this country. This paper aims to collate and appraise historical data for D. reticulatus, to supplement such data with more recent surveillance data and to report on field sampling conducted during 2009-2016. These updated data facilitate better understanding of the current distribution of this tick in the U.K., which will better inform disease risk assessments. There appear to be four known regions of the U.K. in which D. reticulatus currently occurs, including western Wales, North and South Devon, and Essex. The majority of foci are located in coastal sand dunes and maritime grasslands, including grazing marsh. However, more recently the tick has been detected in urban greenspace in Essex. The emergence of this tick as a vector of babesiosis in the U.K. and its recent apparent spread in Essex into urban greenspace highlight the need for continued surveillance and for further research into its status as a vector of human and veterinary pathogens.

Effective inhibition of thrombin by Rhipicephalus microplus serpin-15 (RmS-15) obtained in the yeast Pichia pastoris

The cattle tick (Rhipicephalus microplus) affects cattle industries in tropical and subtropical countries because it is the vector of babesiosis and anaplasmosis which constitutes a threat to the health of cattle. During blooding feeding, ticks secrete saliva containing a complex of bioactive molecules into the injured site to evade host's defensive responses. Serine protease inhibitors (serpins) are important anti-haemostatic molecules present in tick saliva that are necessary for a successful blood feeding. Several serpin sequences have been reported in R. microplus but there is a gap of information about their functions during host–parasite interactions. In this study, the RmS-15 expressed in the yeast Pichia pastoris was characterised using kinetic assays and in vitro analysis. The inhibitory enzymatic assays conducted showed that RmS-15 is a physiological inhibitor of thrombin with a stoichiometric inhibition (SI) of 1.5 and high inhibition affinity with ka=9.3±0.5×104M−1s−1. RmS-15 delayed the clotting of plasma in a dose-dependent manner as determined in a recalcification time assay. Significant elevated ELISA titres were observed in tick resistant and susceptible cattle on day 28 after the tick infestation (p<0.001). This data suggests direct contact of RmS-15 with the immune system of the host at the tick-feeding site. The present study contributed to the understanding of the biological functions of R. microplus serpins during host–parasite interactions which contributes to the design of future innovative methods for tick control.

Epizootiology of Babesia bovis and Babesia bigemina in Free-ranging White-tailed Deer in Northeastern México

Species of Rhipicephalus (Boophilus) ticks are the vectors of babesiosis (cattle fever tick), which are distributed worldwide. White-tailed deer (Odocoileus virginianus) are important secondary hosts for the cattle fever ticks, Rhipicephalus (B.) annulatus and Rhipicephalus (B.) microplus. White-tailed deer are capable of sustaining Boophilus spp. tick populations in the presence or absence of cattle. The objectives of this study were to determine the frequency of Babesia bovis and Babesia bigemina and the prevalence of antibodies to them and identify possible risk factors for bovine babesiosis in white-tailed deer in 3 northeastern states of México. Whole blood and serum samples (n = 457) were collected from white-tailed deer in the states of Coahuila, Nuevo Leon, and Tamaulipas during the spring of 2004. Samples were tested for B. bovis and B. bigemina by nested polymerase chain reaction (n-PCR) (the primers for B. bovis identified the gene Rap-1 and B. bigemina were specific primers) and by an indirect immunofluorescence antibody test (IFAT). A questionnaire was given to each ranch to obtain information about management practices. Logistic regression methods were used to test the association between management factors and the dependent variable of positive n-PCR or IFAT. Nineteen (4.2%) samples were positive to B. bigemina and 6 (1.7%) were positive to B. bovis by n-PCR. Serological testing showed 59.9% (n = 274) of deer sampled were positive to B. bovis and 5.4% (n = 25) were positive to B. bigemina antibodies. The logistic model varied with different dependent variables. With positive n-PCR and B. bigemina as the dependent variable, 3 factors were associated: habitat (presence of brush and exotic grasses; odds ratio (OR), 3.3; 95% confidence interval (CI), 1.3-8.5), grazing system (continuous grazing OR 4.0; CI, 1.3-12.2), and tick treatment frequency (3-4 mo; OR 7.0, CI 1.4-34.3; 5-6 mo; OR, 11.0; CI, 1.9-62.7; > 6 mo; OR, 4.6; CI, 0.9-23.3). These findings suggest that white-tailed deer may act as a reservoir for the 2 bovine Babesia spp. and that white-tailed deer may be important in the epidemiology of babesiosis. However, evidence is not available to support whether white-tailed deer are, or are not, likely to be a host that could complete the transmission cycle of Babesia spp. These results suggest that additional research is needed to demonstrate the importance of white-tailed deer as a Babesia spp. infection source for ticks.

A wet season survey of animal trypanosomosis in Shongom local government area of Gombe state. Nigeria

Two hundred and three (203) blood samples were collected from randomly selected herd comprising; cattle, 68 (33.5%), sheep 57 (28.1%), goats 16 (7.9%), donkey, 3 (1.5%) and pigs 59 (29.1%) respectively. The blood samples were collected from animals and examined in seven villages from two districts (Filiya and Lapan) of Shongom Local Government Area. These total numbers of 203 comprises 47 (23.2%) males and 156 (76.8%) females. From the males, 15 (31.9%) were cattle, 11 (23.4%) sheep, 5 (10.6%) goats, 0 (0.0%) donkey and 16 (34.0%) boar while the females consist of 53 (34.0%) cattle, 46 (29.5%) sheep, 11 (7.1%) goats, 3 (1.9%) donkeys and 43 (27.6%) sow. The blood samples from these animals were analysed using a combination of thin and thick blood films and concentration methods. Eleven (5.42%) were found to be positive for hemoparasites. These comprise. Trypanosoma vivax 1 (9.1%), Microfilariae 1 (9.1%), Babesia 8 (72.7%) and 1 (9.1%) Anaplasma. The average packed cell volume (PCV) for infected and non infected males were 33.1 3.3 and 33.4 1.5 while that of females 31.5 5.1 and 31.9 0.8 respectively. Babesia spp were find to be higher in prevalence 8 (72.7%) while T. vivax, Microfilariae and Anaplasma accounts for least occurrence 1 (9.1%) each. This indicates high prevalence rate of ticks (vector of babesiosis) and absence of Glossina spp biological transmitters of zoonotic trypanosomiasis in the study area.

Vector situation of tick-borne diseases in the Caribbean islands

The most important ticks transmitting diseases to ruminants in the Caribbean islands are: Amblyomma variegatum, vector of cowdriosis and associated with acute dermatophilosis; Amblyomma cajennense, potential vector of cowdriosis; Boophilus microplus, vector of babesiosis and anaplasmosis. At the present time, Amblyomma variegatum is widespread in the Lesser Antilles from Barbados to Puerto Rico. The intensity of the tick control program varies in the different islands and the tick infestation in each island ranges from limited foci to widespread infestations. The vector situation appeared stable since 1988 in the Lesser Antilles but the outbreak in 1992 in Puerto Rico emphasized the risk of spread to other islands and to the American mainland, particularly with cattle egrets. Cowdriosis remains apparently limited to Guadeloupe and Antigua. Amblyomma cajennense, experimental vector of cowdriosis, is present in Cuba, Jamaica and Trinidad but also in most American countries. Boophilus microplus is widespread throughout the Caribbean. Its presence and importance are often indirectly estimated by the clinical and serological diagnosis of babesiosis and anaplasmosis. There is no correlation between the intensity of Amblyomma variegatum control in each island of the Lesser Antilles and the effect on the Boophilus microplus population measured by the seroprevalence to babesiosis and anaplasmosis, but within the island of Martinique a regular Amblyomma variegatum control decreases the seroprevalences to babesiosis and anaplasmosis.

Human Babesiosis on Nantucket Island: Transmission by Nymphal Ixodes Ticks

In order to identify potential vectors of human babesiosis (Babesia microli) in southern Massachusetts, I attempted to transmit the infection via nymphal ticks of that species found to be most abundant on reservoir hosts (Peromyscus leucopus) in nature. Mice were collected at frequent intervals throughout a year in a known enzootic focus on Nantucket Island, and ticks were removed by hand. Ticks of only two species were present; larvae and nymphs of Ixodes scapularis were about 10 times as numerous as were those of Dermacentor variabilis. Accordingly, I. scapularis were used in attempts to transmit a strain of Babesia derived from a human infection recently acquired near the study site. Larvae were permitted to feed on an infected hamster and nymphs derived from these larvae were placed on each of 11 non-infected hamsters. All but one hamster became infected. Nymphs reared from larvae that had attached to a non-infected hamster did not transmit babesiosis to other hamsters. These results suggest that I. scapularis serves as a vector of babesios-s on Nantucket hamsters. These results suggest that I. scapularis serves as a vector of babesiosis on Nantucket Island.