Importance of equine piroplasmosis antibody presence in Spanish horses prior to export.

Serological analysis of equine piroplasmosis (EP), caused by Theileria equi and Babesia caballi, is included in the export testing requirements for most of the countries worldwide, thus involving a high economic impact on equine industry of EP-endemic countries, such as Spain. A total of 3368 serum samples from healthy horses collected prior to export between 2015 and 2018 in Spain were tested for antibodies against T. equi and B. caballi by using a competitive inhibition enzyme-linked immunosorbent assay (cELISA). The overall seroprevalence results in Spain revealed that almost a quarter of the horses analysed (24.1 %; 95% CI 22.6-25.5) could not be exported to countries free from EP. The implementation of prevention measures such as the use of acaricides and daily checks for ticks in horses, as well as regular serological screening of horses in Spain would aid to increase the number of horses exported to other countries.

Zoonotic Babesia: A scoping review of the global evidence.

BACKGROUND: Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis. METHODS: A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori. RESULTS: This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species. CONCLUSION: Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.

A review of the history of research and control of Rhipicephalus (Boophilus) microplus, babesiosis and anaplasmosis in Uruguay.

In Uruguay, control of Rhipicephalus microplus began in 1910. In 1941 the eradication of R. micoplus throughout the country was declared mandatory, although this attempt was unsuccessful. Since 2008 the country was divided into two regions: the south-western region, which is free of ticks; and a region of tick control that includes all departments to the north of the Rio Negro and five departments in the eastern region. In Uruguay, investigations on R. microplus, babesiosis and anaplasmosis started in 1921, and in the 1970s, studies of the epidemiology of R. microplus determined that from 2 to 3.5 generations can be produced annually and that the country is in an area of enzootic instability for babesiosis and anaplasmosis. Knowledge of tick epidemiology and of tick resistance to different acaricides led to the development of efficient methods of control or eradication, including integrated control and generational treatment. Although research results have led to a legal framework regarding R. microplus control, these measures have had variable results. This can be attributed to several factors, such as the discontinuation of the control measures, variable financial resources, changes in the dynamics of livestock movement, failure to adopt available technology for tick control by farmers, climate change, environmental alterations such as forestation and the increasing resistance of ticks to acaricides, which led to the development of multiresistant ticks. This paper reviews the history of R. microplus, babesiosis and anaplasmosis in Uruguay and proposes alternatives for their control.

Cost-effectiveness of Babesia microti antibody and nucleic acid blood donation screening using results from prospective investigational studies.

BACKGROUND: Babesia microti causes transfusion-transmitted babesiosis (TTB); currently, blood donor screening assays are unlicensed but used investigationally. STUDY DESIGN AND METHODS: We developed a decision tree model assessing the comparative- and cost-effectiveness of B. microti blood donation screening strategies in endemic areas compared to the status quo (question regarding a history of babesiosis), including testing by: (1) universal antibody (Ab), (2) universal polymerase chain reaction (PCR), (3) universal Ab/PCR, and (4) recipient risk-targeted Ab/PCR. The model predicted the number of TTB cases, complicated TTB cases, cases averted, and quality-adjusted life years (QALYs). Economic outcomes included each strategy's per-donation cost, waste (number of infection-free units incorrectly discarded), and waste index (number wasted units/number true positives). Sensitivity analyses examined uncertainty in transmission probabilities, prevalence rates, and other key model inputs. RESULTS: Universal PCR in four endemic states would prevent 24 to 31 TTB cases/100,000 units transfused (pht) at an incremental cost-effectiveness ratio (ICER) of $26,000 to $44,000/QALY (transmission probability dependent) and waste index of zero. Universal Ab/PCR would prevent 33 to 42 TTB cases pht at an ICER of $54,000 to $83,000/QALY and waste index of 0.05. The questionnaire is most wasteful (99.62 units wasted pht; 208.62 waste index), followed by the risk-targeted strategy (76.27 units wasted pht; 0.68 waste index). The model predicted zero cases of TTB or complicated TTB with universal Ab/PCR (versus [33, 42] and [13, 18] pht, respectively [no screening]). Results are highly sensitive to transmission probabilities. CONCLUSIONS: Universal PCR in endemic states is an effective blood donation screening strategy at a threshold of $50,000/QALY. Using a higher cost-effectiveness ratio, universal Ab/PCR is the most effective strategy.

Estimated direct economic costs associated with tick-borne diseases on cattle in Tanzania.

Tick-borne diseases, namely, anaplasmosis, babesiosis, cowdriosis and theileriosis, constrain cattle production and improvement in Tanzania, leading to considerable economic losses. A simple spreadsheet model was used to estimate the economic losses resulting from production losses, treatment and control costs associated with tick-borne diseases (TBD) in Tanzania. Model parameters included the national cattle population, reported TBD morbidity, fatality risk, and chemotherapy and control measures used. The total annual national loss due TBD was estimated to be 364 million USD, including an estimated mortality of 1.3 million cattle. Theileriosis accounted for 68% of the total loss, while anaplasmosis and babesiosis each accounted for 13% and cowdriosis accounted for 6% of the total loss. Costs associated with mortality, chemotherapy and acaricide application accounted for 49%, 21% and 14% of the total estimated annual TBD losses, respectively, infection and treatment method milk loss and weight loss accounted for 1%, 6% and 9% of the total annual loss, respectively. Despite the inadequacies of the data used, the results give evidence that tick-borne diseases inflict substantial economic losses on cattle production and resource use in Tanzania.

Survey of canine babesiosis in South Africa.

A questionnaire, designed to obtain qualitative information on a number of variables concerning canine babesiosis (biliary fever) in South Africa, was sent to 510 veterinary practices in late 1993. Of the 157 practices that responded, all were presented with cases of babesiosis and most were situated in Gauteng, the Western Cape and KwaZulu-Natal. Apart from the Western Cape, a winter-rainfall region, the prevalence of babesiosis cases in dogs was highest in summer. Most of the respondent practices treated between 1,000 and 5,000 sick dogs that included 100 to 500 babesiosis cases each year. Respondents identified cerebral babesiosis, enterorrhagia, 'red' or haemoconcentrated babesiosis, acute renal failure and pulmonary babesiosis or 'shock lung', amongst others, as the most prevalent forms of complicated ('atypical') babesiosis. Diminazene, imidocarb and trypan blue were the most popular antibabesials. Trypan blue was most often used in shocked patients, whereas diminazene and imidocarb were preferred when there was a high parasitaemia in the absence of shock. At least 19 antibabesial treatment regimens were used in practices. These comprised the use of single doses of antibabesial drugs; split doses with repeat injections, and combined drug variations, some of which are undesirable due to possible sterilisation of Babesia infection or potential toxicity. Side-effects were most commonly associated with imidocarb use. Ninety-six percent of respondents used supportive treatment (e.g. corticosteroids, vitamins and 'liver support') in all cases of babesiosis. The use of blood transfusion as supportive treatment varied according to practice and severity of the case. Most practices never cross-matched blood to be transfused, and transfusion reactions were rare. Diminazene was most frequently incriminated in cases where drug 'resistance' or relapses occurred. Cerebral and 'red' cases resulted in high mortality. Treatment of babesiosis costs the dog-owning public in South Africa more than R20 million each year. Information on the distribution and possible complicating role of Ehrlichia canis was obtained. Development of a vaccine was the first research priority identified.

General review of tick-borne diseases of sheep and goats world-wide.

A general review of the tick-borne diseases of sheep and goats is given, with the emphasis on those thought to be of greatest economic importance. These include babesiosis, theileriosis, cowdriosis, anaplasmosis, ehrlichiosis, Nairobi sheep diseases and tick paralysis. A commented list of tick-borne diseases and their vectors is presented. It is stressed that large gaps remain in our knowledge of the real importance in the field of many of these diseases, especially in local stock.

Babesiosis in China.

The importance of babesiosis in livestock in China is discussed and mainly focused on bovine and equine babesiosis. Babesiosis is still one of the most important diseases affecting livestock and has caused great economic loss. Nine species of Babesia have been recognized in livestock: B. bigemina, B. bovis, B. major, B. motasi, B. ovis, B. perroncitoi, B. trautmanni, B. equi (Theileria equi), B. caballi. The distribution of Babesia follows the distribution of the tick vectors. The main vectors of bovine babesiosis are the one-host tick Boophilus microplus and the three-host ticks Rhipicephalus haemaphysaloides haemaphysaloides, Haemaphysalis punctata and Haemaphysalis longicornis. Bovine babesiosis has caused significant losses in milk and meat from cattle in most parts of China. The disease is also a barrier to improving productivity of local cattle by cross-breeding due to the high mortality of genetically superior but highly susceptible cattle, especially dairy cattle, imported from Babesia-free areas. Dermacentor nuttalli is the major vector of equine babesiosis and the tick is distributed in almost all parts of North China. Outbreaks of equine babesiosis have not been very common, but in some districts the disease has seriously affected horses, donkeys and mules.

Impact of Babesia bovis and Babesia bigemina on the production of beef cattle in Uruguay.

Uruguay is situated in a marginal area for the development of Boophilus microplus (30 degrees 35 degrees South Lat.) with important areas of enzootic instability for Babesia bovis and B. bigemina. The livestock products represent 70% of our exports, for which reason it is fundamental to evaluate the losses in the production that these haemoparasites cause as basic information to take future decisions. In the period 1988-1990, several works were carried out by our laboratory to know the incidence of babesiosis in the reduction of liveweight gains. The results are shown and discussed in the work. Experiment I: the weight increase of the control group (x = 0.248 kg/day), was 23% higher than that of the infected group with Babesia spp (from Uruguay), but significant statistical differences were not found (P < 0.05). These animals were kept in boxes and the food was controlled for 76 days. Experiment II: the incidence of Babesia spp (same strain) was studied for 140 days on Hereford heifers (n = 14) on natural pastures. The control group obtained x = 25.29 kg of liveweight gain and it was 45% higher than that of the infected group, significant statistical difference were found (P < 0.05). Experiments with attenuated strains III: four studies were carried out inoculating B. bovis and B. bigemina in bovines about one year old, in different growth systems, searching for the limit of application. Significant statistical differences between those groups were not found during the experiment (about 180 days) (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and control of babesiosis in the Americas.

This review presents up-to-date information on the distribution and control measures of babesiosis in Latin America. Bovine babesiosis caused by Babesia bovis and B. bigemia will be emphasized. The disease is endemic in most countries and poses a serious economic burden on livestock production in the region (U.S. $1365 million/year, FAO, 1989). Of the estimated 250 million cattle in Central and South America, approximately 175 million (70%) are in tick-infested regions. Humid, tropical and subtropical areas favor development of the main vector, the one-host tick Boophilus microplus. In many regions bovine babesiosis is enzootically stable as a consequence of a balanced host-parasite relationship. However, Latin America offers a wide range of epidemiologic conditions that are influenced by variations from tropical to cool climates and by susceptible purebred cattle that are regularly imported to upgrade local stocks. The control measures employed in most countries for babesiosis essentially rely on chemotherapy, use of acaricides for B. microplus, and to a lesser degree, on immunization methods. In general, these measures are expensive, time consuming, and in many cases, provide limited success. Finally, the zoonotic potential of babesiosis will be addressed, with special emphasis on the situation in the United States. Even though bovine babesiosis has long been eradicated from the U.S.A., human babesiosis is endemic in the northeastern region of the country.