The infection of various tick species with Babesia bigemina, its transmission and identification

Strains of Boophilus decoloratus and B. microplus were easily infected with a single stock of Babesia bigemina; Boophilus annulatus could be infected less easily, and it was difficult to infect Rhipicephalus evertsi. Two strains of R. appendiculatus and one strain each of R. bursa and Hyalomma anatolicum excavatum were refractory. The same stock of B. bigemina was transmitted by nymphs and adults of B. decoloratus but only by nymphs of R. evertsi. Vertical infection was not observed in R. evertsi, whereas it persisted in B. decoloratus for at least two generations. The sporokinetes in the hemolymph of R. evertsi were significantly shorter than those in the three Boophilus species.

The transstadial transmission of Babesia caballi by Rhipicephalus evertsi evertsi

Rhipicephalus evertsi evertsi larvae were fed on the ears of rabbits. Seven days after larval infestation, unfed, newly moulted nymphae were manually removed to infest a splenectomized donkey showing a patent Babesia caballi infection. Engorged nymphae were collected from the donkey and the ensuing adult ticks were placed on a susceptible horse. The horse contracted a B. caballi infection showing a prepatent period of 19 days after tick infestation. A very low parasitaemia, (highest score 2), which was patent for only 10 days, was recorded. The lowest packed cell volume recorded was 16%.

Relationships between Cytauxzoon felis and African piroplasmids

A cat which had recovered from Cytauxzoon felis infection following treatment with the anti-theilerial drug, parvaquone, showed an increase in piroplasm parasitemia after splenectomy and its blood was suitable for the preparation of antigen smears for the indirect fluorescent antibody test. High levels of antibodies were found in this cat after recovery, in two other cats sub-lethally infected with piroplasms and in sera of naturally infected bobcats. Cats recovered from piroplasm infection died from cytauxzoonosis when challenged with organ material containing C. felis schizonts. Tests with piroplasm antigens and positive sera of C. felis, South African Babesia felis and African Theileria taurotragi showed no significant serological relationship between C. felis and the African parasites. C. felis was not shown to be infective for splenectomized sheep.

Seasonal variation of transmission risk of Lyme disease and human babesiosis

The seasonal host-seeking pattern of nymphal Ixodes dammini infected with Babesia microti or Borrelia burgdorferi was determined on Nantucket Island, Massachusetts, during 1985. The peak period of host-seeking by infected nymphal I. dammini occurred in May and June. On a per person-hour basis, the number of infected ticks collected reached a maximum in May (Babesia = 17.3; Borrelia = 16.2). The number of infected ticks remained high in June, but decreased notably in July, August, and September. Transmission risk of the tick-borne etiologic agents of Lyme disease and human babesiosis in Massachusetts is greatest during the late spring-early summer months of May and June.

Simultaneous transmission of Borrelia burgdorferi and Babesia microti by individual nymphal Ixodes dammini ticks

Nymphal Ixodes dammini ticks, selected from a group of ticks in which 22 of 31 (71%) contained dual Borrelia burgdorferi and Babesia microti infections, simultaneously transmitted B. burgdorferi and B. microti to 4 of 7 (57%) hamsters exposed to individual ticks.

Lyme disease and babesiosis: acaricide focused on potentially infected ticks

Permethrin-treated cotton, intended as rodent nesting material, was distributed in wooded sites in which the agents of Lyme disease and babesiosis were enzootic, in order to kill immature Ixodes dammini, the ticks that transmit these human pathogens. Such ticks feed most abundantly on white-footed mice (Peromyscus leucopus), apparently the main reservoir hosts of these agents, and tend to concentrate in mouse burrows. Mice captured after permethrin-treated cotton was distributed, were infested by a tenth as many ticks as were those captured in adjacent nontreated sites, a difference that continued throughout the 4-month period of observation. On average, 72% of all mice captured in treated sites were free of ticks, while virtually all mice captured in nontreated sites were infested. Voles (Microtus pennsylvanicus), however, were tick-infested, regardless of site of capture. Laboratory-reared I. dammini failed to attach to mice captured in treated sites, and most such exposed ticks died. Distribution of permethrin-treated cotton appears to be a means for preventing transmission of the pathogens that cause human babesiosis and Lyme disease.

Selected arthropod-borne diseases. Plague, Lyme disease, and babesiosis

The incidence of plague, one of the oldest arthropod-borne diseases, has increased during the past 10 years in the United States. Domestic carnivores are playing an increased role in the occurrence of human cases. The cat is now the principal cause of primary human pneumonic plague in the United States. Lyme disease and babesiosis, which were initially thought to be limited to specific local regions, are much more widespread than originally thought.

Experimental infections of Babesia bigemina in American bison

Babesia bigemina was experimentally transmitted from cattle to bison and back to cattle. One spleen-intact and two splenectomized American bison (Bison bison) inoculated with a B. bigemina stabilate exhibited clinical and hematological signs of babesiosis within 10 days of exposure. Blood from the infected bison produced disease in a splenectomized bovine steer.

The inability of a South African Babesia bovis vaccine strain to infect Boophilus microplus

A strain of Babesia bovis that had been attenuated by rapid syringe passage through a series of 23 splenectomized calves was unable to infect its vector Boophilus microplus. An attempt to transmit the attenuated Australian Babesia bigemina G strain with a South African strain of B. microplus was likewise unsuccessful. The epidemiological implication of these observations in terms of babesiosis control is discussed.

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)

Bovine babesiosis (Babesia bovis infection) in Zambia

Two cases of Babesia bovis, a parasite associated with the tick Boophilus microplus, are reported for the first time from the central part of Zambia. It is concluded that infected B. microplus ticks are occasionally introduced into central Zambia by tick-infested cattle from the north-eastern part of the country where B. bovis is endemic. The spread of B. microplus in Southern Africa in a westward direction is discussed and related to the epidemiology of bovine babesiosis in Zambia.

Ixodid tick attacks on man in Israel: medical implications

Various species of ixodid ticks that have been recorded to attack man were surveyed, and boutonneuse fever caused by Rickettsia conorii, which is transmitted in Israel by Rhipicephalus sanguineus s.l., is reviewed. Only in one case were a complement fixation test and exact determination of the species of the tick performed. Tick toxicosis and tick paralysis are discussed, and the possibility of human babesiosis and Lyme disease or erythema chronicum migrans appearing in Israel is considered.

Babesiosis in Wisconsin. A new focus of disease transmission

A confirmed case of human babesiosis was identified in August 1983 in a 54-year-old asplenic Wisconsin resident. Babesia microti was identified as the causative agent by blood smear morphology and hamster inoculation techniques. The patient's wife had clinically confirmed Lyme disease in 1981 and had serologic evidence (immunofluorescent antibody to a B microti titer of 1:1,024) of recent Babesia infection in August 1983. Mice (Peromyscus species) trapped on the patients' property and elsewhere in their Wisconsin county of residence were infected with B microti. Lyme disease and babesiosis have the same tick vector and animal reservoir; serum samples from 116 Wisconsin and Minnesota residents with clinically confirmed Lyme disease between 1980 and 1983 were tested, and none were found to have concurrent Babesia infection. This area of Wisconsin is identified as a new focus for babesiosis transmission, but the risk of transmission seems to be low.

[Autochthonous babesiosis in dogs in the Netherlands?]

For the first time cases of babesiosis have been diagnosed in dogs that had not been abroad. Three cases were seen in the province of Gelderland (Bennekom, Elspeet), two in North-Holland (Koog aan de Zaan). A female Dermacentor reticulatus tick, the main vector of the disease in Europe, was found on one of the dogs at Koog; previously specimens of this tick species had only occasionally been seen on dogs returning from abroad. Serological evidence was obtained that in at least four of the cases European Babesia canis, transmitted by Dermacentor ticks, was involved.

Adult Respiratory Distress Syndrome in Babesiosis

A patient is described who contracted transfusion-induced babesiosis, and later developed acute respiratory distress syndrome (ARDS) as a fatal complication. ARDS has been reported in patients with Plasmodium falciparum malaria, but to our knowledge has not been observed as a complication of babesiosis.

[Transmission and course of parasitemia of Babesia microti (Hannover I strain) in the bank vole (Clethrionomys glareolus) and field vole (Microtus agrestis)]

In Germany only M. agrestis has been found to be naturally infected with B. microti while in other European countries several rodent species were found as mammalian hosts. In the laboratory C. glareolus got easily infected by German strains of B. microti, if parasitized blood was inoculated. But results of this method are not transferable to natural conditions. Therefore this study was carried out. It was to prove whether C. glareolus is susceptible to B. microti transmitted by nymphs of I. ricinus, or not. To compare the results, M. agrestis was infected in the same way. Both of them proved to be susceptible. The parasitaemia lasted for months. In the beginning the rate of parasitaemia reached 2%, then decreased below 0.1%. The course of infection was variable. In blood smears B. microti could not be detected at all times, so that in field trials the infection rate in mice will often be underestimated. A connection between parasitaemia and gravidity or lactation was not observed under laboratory conditions.

[An outbreak of babesiosis in Eastern Flevoland]

An outbreak of babesiosis, with Babesia divergens as the causative agent, occurred in a herd in one of the more recently reclaimed polders involving at least 12 animals. Pasture investigation by blanket-dragging revealed a population of Ixodes ricinus ticks, living in and near the approximately fifteen-year-old afforestation. The differential diagnosis and possible routes by which the disease is introduced, are discussed.