Economic impact of ticks and tick-borne diseases on cattle production systems around Lake Mburo National Park in South Western Uganda

A longitudinal economic impact study of Ticks and Tick-Borne Diseases (TTBDs) in cattle around Lake Mburo National Park (LMNP) was done. Impact was valued using Uganda Shilling (Ug. Shs) (exchange rate of 1USD to Ug. Shs 1,420). The costs for controlling TTBDs was constituting 85.6 ± 3.2% (pastoral) and 73.8 ± 4.2% (ranches) to total disease control costs. The main costs were on tick control, constituting 83.1% (ranches) and 87.9% (pastoral). In pastoral herds, the costs were negatively correlated to herd size (r = −0.99). The mean annual cost per cattle for controlling TTBDs for ranch and pastoral herds was similar Ug. Shs 5,900 ± 545. The mean annual Economic Cost (EC) of TTBDs per cattle was not significantly different (p > 0.05) between pastoral (Ug. Shs 6,700 ± 580) and ranch herds (Ug. Shs 7,600 ± 970). The mean annual EC per cattle was negatively correlated (r = −0.99) with herd size in pastoral systems contrary to positive correlation (r = 0.99) observed among the ranches. The major component of EC of TTBDs of 88.2% (pastoral) and 78.6% (ranches) was due to their control. The other component was owed to mortality, which was positively correlated (p < 0.01) to the ranch herd size. The total annual EC of TTBDs around LMNP was Ug. Shs 437,754,600 (USD 308,144).     

Epidemiology of tick-borne diseases of cattle in Zimbabwe. I. Babesiosis

Summary A survey on the incidence of antibodies toBabesia bigemina andBabesia bovis in one to three year old calves at 274 localities in Zimbabwe revealed thatB. bigemina occurred throughout the country together with its main vector,Boophilus decoloratus. The distribution ofB. bovis followed closely that of its vectorBoophilus microplus which is limited to the eastern part of the country. Enzootic stability forB. bigemina was recorded in most of the communal tribal areas where regular dipping of cattle had been interrupted for several years but was less common on commercial farms where regular dipping is practised. Enzootic stability forB. bovis was restricted to a few localities in communal areas and the parasite was rare on commercial farms.

---

Epidemiologia De Las Enfermedades Transmitidas Por Garrapatas En Zimbabwe. I. Babesiosis

Resumen Se llevó a cabo un estudio de a incidencia de anticuerpos deBabesia bigemina yBabesia bovis, en terneros en edades comprendidas entre uno y tres años, en 274 localidades de Zimbabwe. Los resultados revelaron, queB. bigemina existe en todo el pais conjuntamente con su vector principal,Boophilus decoloratus. La distribuición deB. bovis siguió aquélla de su vectorBoophilus microplus, el cual existe únicamente en la parte oriental del pais. La estabilidad enzoótica deB. bigemina fué notoria en la mayoria de regiones en donde los baños garrapaticidas habían sido interrumpidos por varios años. En las regiones en donde se practicaban baños regulares en fincas comerciales, ésta fué menos manifiesta. La estabilidad enzoòtica deB. bovis estuvo restringida a unas pocas localidades de pastoreo comunal y la presencia de parásitos fué rara en fincas o hatos comerciales.

---

Epidemiologie Des Maladies Des Bovins Transmises Par Les Tiques Au Zimbabwe. I. Babesiose

Résumé Une enquête sur l'incidence des anticorps deBabesia bigemina etBabesia bovis chez des veaux âgés de l à 3 ans dans 274 localités du Zimbabwe a révélé queB. bigemina était présente dans tout le pays avec pour vecteur principalBoophilus decoloratus. La répartition deB. bovis suivait de près celle de son vecteurBoophilus microplus qui est limité à la partie est du pays. La stabilité enzootique pourB. bigemina a été notée dans la plupart des régions d'élevage traditionnel où le traitement des bovins par bains détiqueurs a été interrompu depuis plusieurs années; mais elle était moins courante dans les fermes industrielles où ces bains sont pratiqués régulièrement. La stabilité enzootique pourB. bovis était réduite à quelques localités des régions d'élevage traditionnel et le parasite était rare dans les fermes industrielles.

     

Epidemiology of tick-borne diseases of cattle in zimbabwe. II. Anaplasmosis

Summary A survey on the incidence of antibodies toAnaplasma marginale in one- to three-year-old cattle was carried out in Zimbabwe using the capillary tube agglutination test. Antibodies were detected in all but one of 118 batches of sera collected from different localities throughout the country. There was no clear relationship between the frequency of occurrence of positive serological reactors, which was similar in both commercial and communal farming areas, and the incidence of clinical anaplasmosis. However, the highest numbers of cattle exhibiting positive reactions were generally recorded from the areas that were most heavily tick infested. There was evidence that wild ungulates may serve as reservoirs of infection as antibodies toA. marginale were detected in sera from buffalo (Syncerus caffer) and impala (Aepyceros melampus).

---

Epidemiologia De Enfermedades Hematozoaricas En Zimbabwe. II. Anaplasmosis

Resumen Se llevo a cabo un estudio de la prevalencia de anaplasmosis (Anaplasma marginale) en Zimbabwe, utilizando la prueba de aglutinación en tubos capilares. Se detectaron anticuerpos en todos, menos en un grupo, de 118 muestras de suero colectadas en diferentes localidades através del país. No hubo correlación entre reactores positivos de áreas de pastoreo comerciales y comunales, y casos de anaplasmosis clínica. Sinembargo, el número más alto de reactores correspondió, al área de pastoreo más infestada de garrapatas. Hubo evidencia, que animales salvajes de pezuña endida, servian posiblemente de portadores de la infección, debido a que se encontraron anticuerpos deA. marginale en suero de búfalos (Syncerus caffer) e impala (Aepyceros melampus).

---

Epidemiologie Des Maladies Transmises Par Les Tiques Chez Les Bovins Au Zimbabwe. II. Anaplasmose

Résumé Une enquête sur l'incidence des anticorps dus àAnaplasma marginale chez des veaux de un à trois ans a été effectuée au Zimbabwe en utilisant le test d'agglutination en tube capillaire. Les anticorps ont été décelés dans tous les cas sauf un des 118 lots de sérum recueillis dans les différentes localités du pays. Il n'y a eu aucune relation apparente entre la fréquence de l'apparition de réactions sérologiques positives, qui était semblable dans les régions d'élevage industriel et d'élevage villageois et l'incidence d'anaplasmose clinique. Cependant les effectifs les plus élevés de bovins positifs ont été généralement localisés dans les régions les plus fortement infestées par les tiques. Il semblerait que les ongulés sauvages agissent comme réservoirs de l'infection puisque des anticorps àA. marginale ont été décelés dans des sérums de buffles (Syncerus caffer) et d'impalas (Aepyceros melampus).

     

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.     

The epizootiology and control of heartwater and other tick-borne diseases of cattle in South Africa

The history of the main bovine tick-borne diseases occurring in South Africa and the role Onderstepoort played in their identification and control is briefly reviewed. The present attitudes regarding the control of tick-borne diseases, taking into account their complexity, is discussed. Gaps in our knowledge regarding heartwater epizootiology and possible future studies are defined.     

犬的蜱传播性疾病

一、犬巴贝氏虫病 犬巴贝氏虫和吉氏巴贝氏虫是犬巴贝氏虫病的病原,血红扇头蜱是犬巴贝氏虫的传播媒介,犬是犬巴贝氏虫的储存宿主。摄入犬巴贝氏虫的任何时期的血红扇头蜱都具有传染性。血红扇头蜱摄入犬巴贝氏虫后2～3天就可以传染给犬。     

Epidemiology of tick-borne diseases of cattle in Zimbabwe. III.Theileria parva group

Summary A survey of the occurrence of antibodies toTheileria parva using the IFA test in calves up to one year old at 244 localities in Zimbabwe revealed that the parasite occurred throughout the country although the prevalence of positive serological reactors was generally low. Outbreaks of theileriosis in high rainfall areas in the north, east and west of the country were attributed toTheileria parva bovis transmitted from cattle to cattle byRhipicephalus appendiculatus. Outbreaks in high and low rainfall areas in the south and west of the country were attributed toTheileria parva lawrencei transmitted from buffalo to cattle byRhipicephalus zambeziensis orR. appendiculatus. R. appendiculatus was not uniformly distributed in Zimbabwe. It occurred very commonly in foci in the commerical farming areas but was rare in most overgrazed communal farming areas. Outbreaks of disease attributed toT. parva bovis were recorded in some but not all theR. appendiculatus foci. The disease was present in areas infested withR. zambeziensis but it did not cause cattle deaths in these areas.

---

Resumen Un reconocimiento de la ocurrencia de anticuerpos deTheileria parva en terneros jóvenes hasta de un a no, llevado a cabo en 244 localidades de Zimbabwe boereveló, que el parásito se encuentra diseminado en todos pais, a pesar que le prevalencia de reactores positivos fue baja. Los brotes de Theileiriosis en las áreas lluviosas y húmedas en el norte, este y oeste del pais fueron atribuídes aTheileria parva laurencei, transmitida de búfalos a ganado bovino, por la garrapataRhipicephalus zambeziensis oR. appendiculatus. ElR. appendiculatus no se encontró uniformemente distribuído en Zimbabwe; se encontró preferentemente en explotaciones comerciales, pero no en áreas comunales de pastoréo. Brotes atribuíbles aT. parva bovis, se enconta?ron en focos deR. appendiculatus. La enfermedad, e estaba presente en áreas infestadas conR. zambeziensis, pero no causó mortalidad. Se consideran datos seroepidemiológicos, en la formulación de regímenes de vacunación para anaplasmosis y babesiosis.

---

Résumé Une enquête concernant l'incidence des anticorps àTheileria parva chez des jeunes veaux de 0 à 1 an a été menée au Zimbabwe dans 244 localités. Le test de l'immunofluorescence indirecte a été utilisé. Cette enquête a montré que le parasite est présent dans tout le pays bien que la fréquence de réactions sérologiques positives soient généralement faible. Les épidémies de theileriose dans les zones à forte pluviosisté du nord, de l'est et l'ouest du pays sont attribuées àTheileria parva bovis transmits de bovin à bovin parRhipicephalus appendiculatus. Les épidémies dans les zones à forte et faible pluviosité du sud et de l'ouest du pays sont attribuées àTheileria parva lawrencei transmis du buffle aux bovins parRhipicephalus zambeziensis ouR. appendiculatus. La répartition deR. appendiculatus n'est pas uniforme au Zimbabwe. La présence est fréquente en foyers dans les zones d'élevage industriel mais elle est rare dans la plupart des zones surpaturées d'élevage traditionnel. Des épidémies de la maladie atribuée àTh. parva bovis ont été entegistrées dans quelques foyers àR. appendiculatus mais pas dans tous. La maladie était présente dans les zones infestées parR. zambesiensis mais elle n'a pas entrainé la mort des bovins.

     

Epidemiology of tick-borne diseases of cattle in Botshabelo and Thaba Nchu in the Free State Province

A seroepidemiological study was conducted on 151 cattle from the Botshabelo and Thaba Nchu areas in the central Free State Province of South Africa, two areas where small scale, peri-urban cattle farming is practised. An indirect fluorescent antibody test was used to test for Babesia bigemina and B. bovis antibodies. To test for Anaplasma marginale antibodies a competitive inhibition enzyme-linked immunosorbent assay method was used. There were no significant differences in serological test results between the cattle from Botshabelo and those from Thaba Nchu. The herd (two areas combined) had an average seroprevalence of 62.42% to B. bigemina, 19.47% to B. bovis and 98.60% to A. marginale. Based on the percentage of cattle that were seropositive to B. bigemina the immune status of cattle in the Botshabelo-Thaba Nchu area is approaching a situation of endemic stability. With reference to A. marginale, the high seroprevalence is indicative of a situation of endemic stability. The occurrence of B. bovis antibodies in the cattle is difficult to explain as Boophilus microplus ticks do not occur in the area in which the study was conducted.     

Ticks and tick-borne disease in Guatemalan cattle and horses

Blood samples and ticks were collected from 48 cattle and 74 horses from seven sites in the Peten region of Guatemala. Data on body condition, mucous membrane capillary refill time and tick infestation levels were recorded for each animal in the study. Horses had significantly higher levels of tick infestation than cattle, as well as poorer body condition scores. Seroprevalence of Babesia spp. was 95.8% for B. bovis in cattle, 89.6% for B. bigemina in cattle, and 92.7% for B. equi in horses. Seroprevalence of Anaplasma marginale in cattle was 87.5%, similar to reports in animals from other regions of Central America. This is the first time that A. phagocytophilum has been reported in animals from this region, with overall PCR-prevalence of 27.6% in cattle and horses, and seroprevalence of 28.4% (52% in cattle and 13% in horses). An agent was identified with serological cross-reactivity and close genetic relatedness to Ehrlichia ruminantium, but further testing confirmed that the agent in Guatemalan cows was not the agent of heartwater. Ticks were identified to species with the predominant species identified on cattle as Boophilus microplus and Amblyomma cajennense, while Anocentor nitens and A. cajennense were most commonly found on horses. Prevalence of infection, tick infestation levels, host factors and environmental data were analyzed for association; A. nitens was significantly associated with A. phagocytophilum prevalence by village.     

Epidemiological analysis of tick-borne diseases in Zambia

Tick-borne diseases are a constraint to livestock production in many developing countries as they cause high morbidity and mortality, which results in decreased production of meat, milk and other livestock by-products. The most important tick-borne diseases of livestock in sub-Saharan Africa are East Coast fever (caused by Theileria parva), babesiosis (caused by Babesia bigemina and B. bovis), anaplasmosis (caused by Anaplasma marginale) and heartwater (caused by Ehrlichia ruminantium). Despite their economic importance, information on the epidemiology of these diseases in many countries, including Zambia, is often inadequate, making rational disease control strategies difficult to implement. In this study 18S and 16S rRNA gene PCR assays were used for a comprehensive epidemiological analysis of tick-borne disease of cattle in three provinces of Zambia (Lusaka, Central and Eastern). All the disease pathogens under study (T. parva, T. mutans, T. taurotragi, B. bovis, B. bigemina, Anaplasma spp and E. ruminantium) were prevalent in each of the provinces surveyed. However, variation was observed in prevalence between regions and seasons. There was no association between live vaccination against East Coast fever and being PCR positive for T. parva. A number of risk factors were shown to be associated with (a) the occurrence of tick-borne pathogens in cattle and (b) cattle tick burdens in the wet season. A negative association was observed between the number of co-infecting pathogens and the erythrocyte packed cell volume (PCV) of carrier cattle.     

Some aspects of tick-borne diseases of British sheep

The significance of tick-borne fever (TBF) and other tick-borne diseases of British sheep are reviewed. Experimental and field studies were carried out to clarify the role of TBF as a pathogen per se and as a predisposing factor in other diseases. Experimental TBF infection caused anorexia and depression in two- to three-week-old lambs, which under the stress of a hill environment could alone be a cause of mortality. Nine out of 10 lambs experimentally inoculated with Staphylococcus aureus during the febrile phase of a TBF reaction developed pyaemic lesions compared with four out of 20 lambs inoculated with S aureus alone. Specific pathogen-free lambs inoculated with an aerosol of Pasteurella haemolytica serotype A1 during a TBF reaction showed more severe clinical signs and had more extensive pathological changes at necropsy than control lambs given P haemolytica alone. Dual infection with TBF and louping-ill virus showed that not only were dually infected sheep more susceptible to louping-ill but almost all of them succumbed to a haemorrhagic syndrome involving a systemic mycotic infection with Rhizomucor pucillus. None of eight sheep given louping-ill virus alone developed this syndrome. Field studies indicated that morbidity and mortality in lambs in south-west Scotland could be markedly reduced by dipping and long acting antibiotic prophylaxis. Lamb groups in which both of these were carried out incurred losses of only 0.6 per cent compared with 10.3 per cent in control groups. In addition antibiotic-treated lamb groups demonstrated significantly better weight gains than untreated groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiology of bovine tick-borne diseases in southern Italy

This investigation was carried out in an area covering part of three southern Italian regions: Campania, Basilicata and Apulia. Eighty-one farms were involved using the formula suggested by Thrusfield; they were equally distributed over the area which was subdivided into 81 geo-referenced sub-areas. In May and June 1999 from a total of 506 cattle, older than 18 months, blood-samples were taken and ticks were collected and identified. Serum samples were tested for antibodies of Bahesia bigemina, Babesia bovis and Anaplasma marginale with an ELISA technique. Eight farms (9.8%) out of the 81 examined were positive for B. bigemina only, 3 (3.7%) for A. marginale only, and 70 (86.4%) for both. None of the animals of any farm was found to be positive for B. bovis. Out of the 506 sera tested, 117 (23.1 %) were positive for B. bigemina only, 58 (11.5%) forA. marginale only and 250 (49.4%) for both species; 81 (16.0%) were negative for all of them. Ticks were collected on animals on 62 (76.5%) out of the 81 farms. Adult ticks (1 410) were collected and identified; the highest number belonged to the Rhipicephalus bursa species (65.5%), followed by Rhipicephalus turanicus (8.6) and Haemaphysalis punctata (8.4). The results showed that B. bigemina, A. marginale and their potential vectors are common in the area examined and indicated that there is a risk for animals imported from tick-borne disease-free areas.     

Forecasting habitat suitability for ticks and prevention of tick-borne diseases

Climate and vegetation are the major factors affecting the distribution of ticks. Consequently, spatial distributions can be analysed by statistical methods that look for correlations between abiotic factors and known data about tick presence/absence. Remote sensing features can be obtained from a wide database of sensors with different characteristics, then applied to the problem of mapping prediction of tick distribution. Some studies had demonstrated that the use of these abiotic variables from satellite imagery has biological significance, therefore statistical accuracy of these distribution models can be interpreted under an ecological framework. Furthermore, models can be linked to these predictive maps, enabling the forecast of spatial and temporal dynamics of ticks, looking for seasonal patterns of activity and accurate use of acaricide treatments.     

工作犬蜱及蜱媒病的预防

<正>今夏,河南发生多起因疑似人被蜱虫叮咬而染病致病的事件,引起了媒体、社会和政府的高度关注。犬是蜱的易感对象,如带犬人与受感染的犬亲密接触,带犬人就有可能受到蜱及蜱媒疾病感染的威胁。为     

Integrated tick and tick-borne disease control trials in crossbred dairy cattle in Malawi

Summary Crossbred dairy heifers on a farm in an East Coast fever (ECF) endemic area in Malawi were immunised againstTheileria parva, Anaplasma spp.,Babesia bigemina, Babesia bovis andCowdria ruminantium. They were treated at infrequent intervals with chlorfenvinphos to limit infestation with adult ticks, without providing complete tick control. In one trial, which tested a threshold dipping regimen, 20 heifers were dipped only once in 6 months to control a flush ofBoophilus microplus. Unimmunised controls showed serological evidence of exposure toT. parva andB. bigemina, and one died of ECF, but there were no incidents of tick-borne disease in the immunised group. In a second trial, which tested a strategic dipping regimen, 107 animals were dipped 9 times over a 6 month period. Despite heavy challenge byB. bovis and moderate challenge byB. bigemina andAnaplasma spp, demonstrated serologically, there was only a single clinical case of babesiosis. The observations provide encouragement for the introduction of integrated tick and tick-borne disease control programmes in improved cattle in ECF endemic areas.

---

Sistemas Integrados De Control De Garrapatas Y Enfermedades Transmitidas Por Garrapatas En Ganado Vacuno Lechero Cruzado En Malawi

Resumen Se inmunizaron terneras lecheras cruzadas frente aTheileria parva, Anaplasma spp.,Babesia bigemina, Babesia bovis yCowdria ruminantium. El experimento se realizó en una granja situada en una zona de Malawi en la que la fiebre de la costa este es endémica. Los animales se trataron de forma infrecuente con clorfenvinfos para limitar la carga de garrapatas adultas, pero no se llevó a cabo ningún programa completo de control de garrapatas. El primer ensayo tuvo como objetivo determinar la frecuencia minima de baños antigarrapata. Un total de 20 terneras recibieron un único baño a lo largo de 6 meses para controlar un aumento en la carga deBoophilus microplus. Los animales control que no habían sido inmunizados mostraron evidencia serológica de exposición aTheileria parva y uno de ellos murió de fiebre de la costa este. Sin embargo, en el grupo de animales inmunizados no se detectó ningún caso de enfermedad transmitida por garrapatas. El segundo experimento tuvo como objetivo comprobar la eficacia de un programa estratégico de baños antigarrapata. Un total de 107 animales fueron bañados 9 veces a lo largo de 6 meses. Si bien se demostró serológicamente una fuerte infestación porBabesia bovis y una infestación moderada porB. bigemina yAnaplasma spp, ningún animal enfermó de babesiosis. Estas observaciones sugieren la conveniencia de introducir programas de control integrados de garrapatas y enfermedades transmitidas por garrapatas en ganado vacuno mejorado en zonas donde la fiebre de la costa este es endémica.

---

Experience De Lutte Integree Contre Les Tiques Et Leurs Maladies Chez Le Betail Hybride Laitier Au Malawi

Résumé Des génisses hybrides productrices de lait furent immunisées contreTheileria parva, Anaplasma spp.Babesia bigemina, Babesia bovis etCowdria ruminantium dans une ferme située dans une région à East Coast fever (ECF). Elles furent traitées à intervalles irréguliers avec du chlorfenvinphos pour limiter l'infestation des tiques adultes, mais sans pourvoir un contrôle complet sur les tiques. Pendant une expérience, qui testa le seuil limite du lavage avec des acaricides, 20 génisses furent lavées une seule fois en 6 mois pour maîtriser l'infestation parBoophilus microplus. Les contrôles, non immunisés, montrèrent des preuves sérolôgiques d'exposition àTheileria parva etBabesia bigemina, et une genisse mourut d'ECF, mais aucun problème de maladie liée aux tiques ne fut observé dans le groupe immunisé. Lors d'une seconde expérience, testant une approche stratégique du lavage avec acaricide, 107 animaux furent lavés neuf fois en six mois. Malgré une infection importante parB. bovis et modérée parB. bigemina etAnaplasma spp., prouvée par étude sérologique, il n'y eut qu'un cas de babésiose. Les observations encouragent l'introduction de programmes de contrôle des tiques et de leurs maladies associées pour améliorer le bétail dans les zones endémiques à ECF.