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Babesial parasites infect cattle in tropical and temperate regions of the world and cause significant morbidity and mortality. Discovery of protective antigens that could be used in a killed vaccine has been slow and to date there are few promising vaccine candidates for cattle Babesia. This review describes mechanisms of protective innate and adaptive immune responses to babesial parasites and different strategies to identify potentially protective protein antigens of B. bovis, B. bigemina, and B. divergens . Successful parasites often cause persistent infection, and this paper also discusses how B. bovis evades and regulates the immune response to promote survival of parasite and host. Development of successful non-living recombinant vaccines will depend on increased understanding of protective immune mechanisms and availability of parasite genomes. [ABSTRACT FROM AUTHOR]

Aim Climate change has the potential to have an impact on the distribution of ticks and tick-borne diseases. This paper identifies the changes in climate suitability for the tick Rhipicephalus (Boophilus) microplus in the Americas by analysing climate data for the period 1950–99. Location The model was applied to the American continent. Methods A model based on Environmental Niche Modelling was used on a gridded (0.5°) long-term (1950–99) climate data set. A map of the core range of the species was constructed, and areas where habitat suitability (HS) changes suddenly over short time periods were identified as regions of high sensitivity. Tendency of climate in the continent was evaluated and scenarios constructed for 2025 and 2050. Results Regions of high sensitivity included the southern USA, Mexico and western and central Argentina. Analysis of climate variables in these regions identified water vapour pressure deficit and evaporation as underlying the high sensitivity of habitat suitability in the USA and Mexico, and showed that episodes of high variability are linked to the El Niño Southern Oscillation. Projections of the tendency of HS as observed for the 1950–99 period point to an increase in this value in parts of the southern USA and in central Argentina, a finding that can be attributed to the progressive increase in minimum and yearly averaged temperatures. Conclusions Short-term changes in climate may drive the system into unstable situations with sudden changes in habitat suitability for the target tick in specific zones of the Americas. Results suggest an increased abiotic (climate) suitability for R. microplus in areas whose habitat is currently unsuitable for this species. [ABSTRACT FROM AUTHOR]

A commercial coproantigen ELISA test for fasciolosis, based on the use of MM3 monoclonal antibody for antigen capture, was investigated for possible cross-reactivity with Paramphistomum cervi, a trematode that commonly infects cattle and sheep grazing in fluke-infested pasture in Ireland. Histological sections of adult and immature Fasciola hepatica and P cervi were incubated with MM3 monoclonal antibody, and its binding to tissue-localised coproantigen was subsequently visualised by immunocytochemistry. In a related study, the soluble antigenic fractions derived from homogenates of P cervi adults and Taenia hydatigena metacestodes were tested for cross-reactivity with MM3 monoclonal antibody in an antigen-capture ELISA, using known F hepatica-positive and F hepatica-negative ovine faecal samples as natural controls. It was found that, while intense immunocytochemical labelling was located over the gastrodermis and gut contents of adult and immature F hepatica, sections of adult and immature P cervi were unlabelled. In the ELISA tests, the soluble fractions of F hepatica reacted strongly with MM3 monoclonal antibody, but those of P cervi and T hydatigena gave negative results. These findings support the specificity of the coproantigen ELISA test for fasciolosis in areas where paramphistomosis and cysticercosis are liable to occur singly or as coinfections with F hepatica. [ABSTRACT FROM AUTHOR]

Aquaculture represents the fastest growing food‐producing sector worldwide. However, the intensification of fish farms has led to environmental, health, and welfare challenges. The monogenean ectoparasite Gyrodactylus spp. has been considered one of the most pathogenic ectoparasites affecting fish, and no specific control strategies besides formalin baths have been established. The use of bioactive plants has been recently proposed as an alternative method to control gyrodactylid infections. Leucaena leucocephala is a tropical legume that has been found with anthelmintic activity against both internal and external parasites of cattle. Therefore, the objective of this study was to assess the anthelmintic‐like activity of L. leucocephala aqueous extract against Gyrodactylus spp. in hybrid tilapia Oreochromis spp. fingerlings and its effect on host health through histopathological analysis. Five concentrations of L. leucocephala aqueous extract were employed (2.00, 1.00, 0.50, 0.25, and 0.125 mg/mL) to estimate the mean effective concentration (EC50). Distilled water and formalin (1:4,000) were used as negative and positive controls, respectively. The aqueous extract of L. leucocephala showed a dose‐dependent behavior, with an EC50 of 0.228 mg/mL. Quercetin was identified as the main phytochemical present in the extract. Postmortem analysis of fingerlings exposed to the plant extract had no treatment‐associated pathological findings, thus indicating that the use of L. leucocephala baths had no negative impact that could jeopardize the lives of treated animals. After the in vivo assessment, the aqueous extract of L. leucocephala appears to be a promising alternative to control gyrodactylid infection in tilapia. [ABSTRACT FROM AUTHOR]

The population dynamics of Rhipicephalus microplus ( Ixodida: Ixodidae) in northwest Argentina was analysed to support the design of strategic methods for its control. Both parasitic and non-parasitic phases were studied. The seasonal activity of R. microplus in its parasitic phase was characterized by three peaks in abundance: the first in mid-late spring; the second in summer, and the third in autumn. The non-parasitic phase of R. microplus was characterized by a long total non-parasitic period observed after exposures of females from mid-summer to early autumn, a short total non-parasitic period observed after exposures of females from late winter to late spring, a short period of larval longevity in early and mid-summer, and no hatch of the eggs produced by females exposed in mid- and late autumn and winter. Treatments of cattle administered during the period from late winter to late spring will act on small cohorts of R. microplus, preventing the emergence of larger generations in summer and autumn. A 17-week spelling period starting in late spring and early summer will be necessary to achieve optimal control of R. microplus free-living larvae. If spelling begins in mid- or late summer or in autumn, the required period will be 26-27 weeks. [ABSTRACT FROM AUTHOR]

The acaricidal effects of 55 strains of Metarhizium anisopliae (Metschnikoff) Sorokin, 1883 (Hypocreales: Clavicipitaceae) isolated from paddocks of cattle farms were evaluated in two Rhipicephalus microplus (Canestrini 1887) (Ixodida: Ixodidae) populations, of which one was multi-resistant and one was susceptible to chemical acaricides. Percentage mortality and reproductive efficiency indices in R. microplus were evaluated by adult immersion tests at a dose of 1 × 108 conidia/mL for each fungal strain. Some strains were selected to calculate lethal concentrations to kill 50% ( LC50) and 99% ( LC99) of engorged ticks. Strains MaV22, MaV26 and MaV55 induced 100% mortality in R. microplus on day 14. Strains MaV05, MaV09 and MaV22 caused mortality of >90% from day 12 onward in both tick populations. The most effective acaricidal fungal strain, MaV55, inhibited egg laying by 54.86 and 55.86% in acaricide-resistant and -susceptible R. microplus populations, respectively. None of the fungal strains had statistically significant effects on larval hatching. In conclusion, nine strains of M. anisopliae demonstrated high acaricidal effects against R. microplus and reduced its egg laying. No differences in acaricidal effects were observed between the two populations of ticks tested. [ABSTRACT FROM AUTHOR]

The article presents a study on acaricide resistance and synergism between amitraz and permethrin against susceptible and resistant strains of Boophilus microplus (Acari: Ixodidae). It is posed that the control of the southern cattle tick, Boophilus microplus (Canestrini) in Mexico and some other countries depends on chemical acaricides. Relative to this, it is forwarded that Boophilus microplus has developed resistance to all major types of acaricides in recent years. In this study, the authors employed larval bioassay techniques to identify levels of resistance to amitraz and permethrin and then assessed synergism between these two acaricides in one susceptible laboratory tick strain and four resistant strains from Brazil and Mexico.

Studies were carried out in Zimbabwe of the responses of tsetse to cattle treated with deltamethrin applied to the parts of the body where most tsetse were shown to land. Large proportions of Glossina pallidipes Austen (Diptera: Glossinidae) landed on the belly (∼ 25%) and legs (∼ 70%), particularly the front legs (∼ 50%). Substantial proportions of Glossina morsitans morsitans Westwood landed on the legs (∼ 50%) and belly (25%), with the remainder landing on the torso, particularly the flanks (∼ 15%). Studies were made of the knockdown rate of wild, female G. pallidipes exposed to cattle treated with a 1% pour-on or 0.005% suspension concentrate of deltamethrin applied to the (a) whole body, (b) belly and legs, (c) legs, (d) front legs, (e) middle and lower front legs, or (f) lower front legs. The restricted treatments used 20%, 10%, 5%, 2% or 1% of the active ingredient applied in the whole-body treatments. There was a marked seasonal effect on the performance of all treatments. With the whole-body treatment, the persistence period (knockdown > 50%) ranged from ∼ 10 days during the hot, wet season (mean daily temperature > 30 °C) to ∼ 20 days during the cool, dry season (< 22 °C). Restricting the application of insecticide reduced the seasonal persistence periods to ∼ 10–15 days if only the legs and belly were treated, ∼ 5–15 days if only the legs were treated and < 5 days for the more restricted treatments. The restricted application did not affect the landing distribution of tsetse or the duration of landing bouts (mean = 30 s). The results suggest that more cost-effective control of tsetse could be achieved by applying insecticide to the belly and legs of cattle at 2-week intervals, rather than using the current practice of treating the whole body of each animal at monthly intervals. This would cut the cost of insecticide by 40%, improve efficacy by 27% and reduce the threats to non-target organisms and the enzootic stability of tick-borne diseases. [ABSTRACT FROM AUTHOR]

Cattle are known reservoirs and asymptomatic excretors of Cryptosporidium, a protozoan parasite that causes severe and protracted diarrhoea in people. The incidence of Cryptosporidium was investigated in 288 matched samples taken from beef carcases of 1 g samples of faeces retrieved immediately after de-legging, 25 cm² samples of beef excised from the rump of uneviscerated carcases, and 25 cm² samples of beef excised from the brisket area of eviscerated carcases. Cryptosporidium species were detected in 21 of the faecal samples after salt flotation and immunofluorescent microscopy. The species isolated from the positive samples were identified by restriction fragment length polymorphism and PCR as Cryptosporidium andersoni (54.5 per cent) and Cryptosporidium parvum genotype 2 (45.5 per cent). In the faecal samples, there was a significantly higher prevalence of the parasite in samples taken in summer (May to July) and winter (November to January) than in spring or autumn. No Cryptosporidium species were recovered from any of the beef samples. [ABSTRACT FROM AUTHOR]

SummaryPrimer sets for five different ungulate loci were used to obtain individual microsatellite DNA profiles for 29 Mashona cattle from a herd in Zimbabwe. There were 3–13 alleles for each locus and, using the entire suite of five loci, each animal within the herd, including closely related individuals, could be unequivocally distinguished. Wild-caught Glossina pallidipes Austen (Diptera: Glossinidae) were fed on specific cattle and the bloodmeal was profiled 0.5–72 h after feeding. The individual specific sources of the bloodmeals, including mixed meals produced by allowing tsetse to feed on two different cattle, were reliably identified up to 24 h after feeding. The technique was used in field studies of host selection by G. pallidipes and G. morsitans morsitans Westwood (Diptera: Glossinidae) attracted to pairs of cattle. When the pair comprised an adult and a calf, 100% of meals were from the adult. For some pairs of adult cattle, tsetse were biased significantly towards feeding on one animal, whereas for other pairs there was no such bias. In general, feeding was greater on the animal known to have a lower rate of host defensive behaviour. Results suggest that relatively slight differences in the inherent defensive behaviour of cattle produce large differences in host-specific feeding rates when the hosts are adjacent. For flies attracted to pairs of cattle, < 2% contained blood from both hosts. The DNA profiling technique will be useful in studying the epidemiology of vector-borne diseases of livestock. [ABSTRACT FROM AUTHOR]

Summary In Zimbabwe, studies were made of the effect of host behaviour on the feeding success of Glossina pallidipes Austen and G. morsitans morsitans Westwood (Diptera: Glossinidae) attracted to cattle of different age and sex. The mean feeding rates for male and female G. pallidipes attracted to oxen were 60% and 58%, respectively, compared to 33% and 53% for male and female G. m. morsitans. The feeding rate of G. pallidipes varied between oxen and was inversely correlated with a host's rate of defensive leg movements, which, in turn, was positively correlated with the density of Stomoxys spp. (Diptera: Muscidae) caught in the vicinity of the host. Tsetse were significantly less successful in feeding from young cattle. For G. pallidipes, the feeding rate on calves (< 6 months) was 11%, whereas for male and female G. m. morsitans the rates were 12% and 20%, respectively. Significantly lower feeding rates were apparent for cattle aged up to 2 years, when the feeding rate for G. pallidipes (31%) was still significantly less than that on mature oxen (68%). Feeding rates for G. pallidipes on adult female cattle were lower than those on oxen (45% vs. 61%). The lower feeding rates in young animals were attributed to higher rates of defensive movements. The results suggest that higher rates of defensive activities by young cattle reduce the risk of them contracting trypanosomiasis. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAb) were produced against midgut membrane (GM) antigens of Boophilus microplus. The isotypes of these mAb were established and their specificity characterized using double diffusion and Western blotting. GM antigens solubilized by Triton X-100 were precipitated by mAb QU13, and the precipitate was then injected into cattle to test for the presence of protective antigens. Vaccinated cattle challenged with 10-day-old larval ticks showed evidence of protection with a 62% reduction in eggs produced by ticks from vaccinated cattle compared to tick eggs from control cattle. In a second vaccine-challenge experiment, the dose of precipitate was increased and >99% protection was provided to these vaccinated cattle following challenge (calculated from tick egg weights compared to the control group). The solubilized antigen(s) precipitated by QU13 were subjected to SDS-PAGE separation and the calculated sizes of these molecules were >200,000, 80,000, 74,000, 62,000, 57,000 and <30,000 MW. [ABSTRACT FROM AUTHOR]

Cryptosporidium andersoni has not been previously reported in feedlot beef cattle in Western Australia. Faecal samples were collected from 10 groups of cattle ranging in age from 11 to 36 months in five different feedlots in Western Australia. The incidence of C. andersoni ranged from 0% to 26%. There were no clinical signs associated with C. andersoni infection, but there was a significant reduction in rate of gain of 0.44 kg in infected animals compared with negative pen mates. Cryptosporidium andersoni is characterised by large oocysts (7.4 × 5.5 µm) and was confirmed by 18S sequencing. [ABSTRACT FROM AUTHOR]