Effect of Anaplasma marginale infection upon blood gases and electrolytes in splenectomized calves.
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Anaplasmosis↗
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Infection of splenectomized calves with Anaplasma ovis.
An Anaplasma was not recovered from 2 splenectomized calves at 17 days after A ovis inoculation, but was recovered from 1 of the calves at 177 days after inoculation. In a 3rd calf exposed to A ovis, an Anaplasma was recovered at 177 and 262 days after inoculation. the Anaplasma recovered from these calves was determined to be A ovis on the basis of cross-infectivity trials, using Anaplasma marginale.
Anaplasma↗
Evaluation of a long-acting injectable oxytetracycline.
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Anaplasmosis↗
Cross reactivity between Anaplasma marginale and two Plasmodium species as demonstrated by passive hemagglutination.
Two types of antigens were prepared from each of 3 partially purified preparations of Anaplasma marginale, Plasmodium lophurae, and P berghei. Hemagglutination tests were conducted with homologous serums to detect antigenic relationships between these organisms. Serums were also absorbed with both homologous and heterologous antigen preparations. Cross reactivity between these organisms was observed.
Anaplasma↗
Isolation of a bovine Theileria.
Dual infections of Anaplasma marginale and a Theileria, resembling Theileria mutans, occurred in splenectomized calves inoculated with pooled blood samples from eastern Texas cattle. Theileria was obtained in pure form by treating dually infected cattle with selectively eliminated Anaplasma. These theileria infections were responsible for mild, transient reductions in packed red blood cell volume (PCV).
Anaplasmosis↗
Blood parasites of some wild bovidae in Botswana.
Blood smears from a total of 282 wild Bovidae from Ngamiland, Botswana were examined for the presence of blood parasites. The following species were sampled: 190 African buffalo, 23 impala, 10 blue wildebeest, 18 tsessebe, 1 eland, 13 lechwe, 16 kudu and 11 sable antelope. In addition, blood from 36 of the above antelope and from a further 48 buffalo was inoculated into rodents to test for the presence of trypanosomes. An anaplasm morphologically indistinguishable from Anaplasma marginale Theiler, 1910 was found in 28,4% of buffalo. The incidence of detectable cases of A. marginale infection in buffalo less than 5 years of age was significantly higher than in those 5-10 years of age (P less than 0,02). Furthermore, the level of parasitaemia was higher in young than in old buffalo. Theilerail piroplasms were found in all 8 species and were detected in 16,3% of buffalo. Two morphological types were found in impala; clinical cytauxzoonosis was suspected in 1 impala. A large Babesia occurred in the erythrocytes of 1 blue wildebeest. Erythrocytic discrasia, associated with the presence of a small Babesia was found in 1 tsessebe. Trypanosoma (Nannomonas) congolense was found in blood smears from 4 buffalo, 1 impala, 1 lechwe and 1 kudu and T. (Trypanozoon) brucei occurred in smears from 2 buffalo and 1 kudu, but all 84 rodent inoculations were negative. The overall incidence of trypanosome infections detected was 2,5% in buffalo and 4,3% in the other species. Protozoa resembling the cyst organisms of Sarcocystis spp., probably originating from cysts ruptured accidentally, occurred in the blood films of 2 impala and 1 tsessebe. The parasite Haematoxenus was not detected in any of the blood smears. The findings are compared with those of workers in other African countries and the importance of blood parasites in wild animals is discussed.
Anaplasmosis↗
Field observations on the duration of immunity in cattle after vaccination against Anaplasma and Babesia species.
In an outbreak of Babesia bovis in a large herd of Friesian x Malawi Zebu cattle, which occurred after an interruption of intensive dipping, clinical or fatal babesiosis occurred in 54/299 (18.1%) animals which had never been vaccinated, as compared to 9/153 (5.9%) vaccinated animals. Eight of the nine affected vaccinates had been vaccinated more than 27 months previously. Sera were collected every 3-4 months from 33 Friesian x Malawi Zebu heifers maintained with intensive dipping and vaccinated with trivalent B. bovis, Babesia bigemina and Anaplasma centrale vaccine. After 2 years, 25% had become seronegative for B. bovis by indirect immunofluorescence, as compared to 97% for B. bigemina and 46% for A. centrale. Because of the evidence that immunity following vaccination against B. bovis declines after 2 years in the absence of tick challenge, it is recommended that tick control should be relaxed after immunity has been established, in order to save acaricide, reinforce immunity and avoid any need for revaccination.
Anaplasma↗
Anaplasma marginale: detection of carrier cattle by PCR-ELISA.
A highly sensitive and specific polymerase chain reaction (PCR) based assay for the detection of the minute levels of Anaplasma marginale present in the blood of long-term carrier cattle was developed. A simple lysis method was used to remove most of the haemoglobin from the blood to facilitate direct input of samples into the PCR reactions without prior purification of the DNA. PCR product was detected by enzyme-linked immunosorbent assay (ELISA) to simplify the processing of large numbers of samples. The sensitivity limit of the PCR-ELISA was 0.00015% parasitaemia (24 infected erythrocytes per microlitre of blood). No cross-reactivity of the assay was observed when A. marginale-negative blood infected with Babesia bovis or Theileria orientalis was tested. The PCR-ELISA was shown to be 92% efficient in the detection of long-term A. marginale carrier cattle. No false-positive results were obtained. These results compared favourably with 2 serological assays for detection of A. marginale carrier cattle (card agglutination test and ELISA) which were applied to the same experimental animals.
Agglutination Tests↗
The distribution of Dermacentor hunteri and Anaplasma sp. in desert bighorn sheep (Ovis canadensis).
The ixodid tick Dermacentor hunteri has been collected intermittently this century, primarily from desert bighorn sheep (Ovis canadensis). Anaplasma spp. are intraerythrocytic rickettsial parasites of ungulates and are vectored in the western United States by ticks of the genus Dermacentor. We tested the hypotheses that D. hunteri would be found infesting all populations of desert bighorn, and that all infested populations would be seropositive for Anaplasma sp. Dermacentor hunteri was found on desert bighorn throughout their range in the Mojave and Sonoran deserts of the southwestern United States and northern Mexico, but not in any portion of the Chihuahuan desert of New Mexico and eastern Arizona or in Baja California Sur, Mexico. Using an indirect immunofluorescence antibody test (IIF), 8 populations of desert bighorn in California with D. hunteri were seropositive for Anaplasma sp. (n = 160). Four populations of desert bighorn with D. hunteri in Arizona (n = 69), 1 in Nevada (n = 22), and I in Utah (n = 14) with D. hunteri were seronegative. Six populations of desert bighorn were uninfested with D. hunteri and were also seronegative. Of these populations, 1 was in California (n = 19), 2 were in New Mexico (n = 33), 2 were in Utah (n = 30), and 1 was in Baja California Sur (n = 14). We found no support for either of our original hypotheses and concluded that both D. hunteri and Anaplasma sp. are limited in their distribution among desert bighorn. We also suggest a cautionary approach to translocations of desert bighorn given the high prevalence of ticks and the unknown effects of Anaplasma sp. on free-ranging bighorn.
Anaplasma↗
Cell-mediated immunity related to challenge exposure of cattle inoculated with virulent and attenuated strains of Anaplasma marginale.
Cattle which were given virulent Anaplasma marginale as a premunization procedure or were vaccinated with live attenuated or killed anaplasma preparations were challenge inoculated with virulent A marginale. Exposure of cattle to virulent or attenuated A marginale, which induced a strong and lasting cell-mediated response as measured by the leukocyte migration-inhibition test, protected against the development of high parasitemia, anemia, and clinical signs of disease after challenge inoculation with virulent A marginale. Cattle which were vaccinated with killed anaplasma preparations that induced transient and low-level cell-mediated responses were not protected against the development of severe anemia after challenge inoculation, although postchallenge parasitemia seemed to be controlled.
Anaplasma↗
Morphologic alteration of Paranaplasma caudata following treatment of calves with oxytetracycline.
The morphologic features of Paranaplasma caudata were determined in whole blood, blood clots, and liver biopsy specimens after treating infected calves with oxytetracycline. Following staining of blood smears with new methylene blue, light microscopy showed that paranaplasma bodies in erythrocytes of treated calves were vacuolated, but tails were normal in appearance. By electron microscopic examination of parasitized erythrocytes of treated calves, paranaplasma bodies were found to be degenerated (aggregation of nucleoprotein granules in initial bodies and condensation and coalescence of initial bodies), but tails were normal. The identical degenerative changes of paranaplasma bodies and lack of alteration of tails were evident in erythrocytes in sinusoids of liver biopsy specimens from treated calves.
Anaplasmataceae↗
Infectivity of Anaplasma marginale after ingestion by potential insect vectors.
Anaplasma marginale-infected erythrocytes retained viability and infectivity for at least 3 days after ingestion by Hippelates pusio Loew and up to 2 days after ingestion by species of Tabanidae. The organism does not appear to have a developmental sequence in the insect vector.
Anaplasma↗
[Clinical and hematological changes in calves infected with Anaplasma marginale].
Clinical and hematological changes of six Anaplasma marginale (isolated Zulia) inoculated calves (experimental group) and four healthy calves (control group) were studied during twenty and eighty days before and after infection, respectively. The behavior of the four calves used as control group was stable and no significant changes in the parameters analyzed was observed. The experimental group developed the three typical phases of illness. During the prepatent phase, which lasted a mean of 21.2 +/- 2.56 days, the animals were asymptomatic and no significant changes in the hematological values occurred, but a remarkable transitory decrease in number of lymphocytes from 6.5 x 10(6) to 3.3 x 10(6) cells/ml. The infection during the acute phase produced a highly severe effect in two animals, a severe effect in three animals and a mild effect in one. The effects observed were the following: 1) a fast decrease in haematocrite, ranging from 6 to 10%; 2) values of parasitaemia varied from 15 to 48%; 3) a greater body temperature than the control animals (40.5 vs. 38.5 degrees C); 4) a elevated heart frequency, from 60 to 110 beats/min; 5) an increase in the concentration of neotrophiles from 10 x 10(6) to 13 x 10(6) cells/ml; 6) The number of monocytes also augmented from 3 x 10(6) to 6 x 10(6) cells/ml; and 7) an important decrease of weight gain. The natural course of infection was interrupted with oxytetracycline when the haematocrite of the animal lowered to values less or equal to 10%. Then, the animals showed a rapid recovery with an undetectable parasitaemia and concomitant return to basal line of the rest of the parameters.
Anaplasmosis↗
Effects of temperature and time on the infectivity of Cryogenically preserved samples of Anaplasma marginale- infected erythrocytes.
The effects of temperature (25 C) and time (2, 4, 6, 8, 12, 24, 48, 72, 96 hours and 5, 13, and 19 days) were determined on thawed samples of Anaplasma marginale-infected erythrocytes cryogenically preserved with dimethyl sulfoxide and frozen in liquid nitrogen. Inoculation into splenectomized calves indicated that infectivity was not destroyed by either time or temperature from 2 to 72 hours, but was destroyed at 96 hours. The incubation periods of the disease in inoculated splenectomized calves increased in proportion to the length of time the samples were held at 25C.
Anaplasma↗
Survival of Anaplasma marginale in Aedes albopictus cells.
Bovine red blood cells infected with Anaplasma marginale were introduced into cell line cultures from the mosquito Aedes albopictus. The cultured mosquito cells phagocytized both infected and uninfected red blood cells. The parasite remained viable, as determined by calf inoculations, for 21 days.
Aedes↗
Tick-borne diseases of sheep and goats caused by Babesia, Theileria or Anaplasma spp.
A review is given on the Babesia, Theileria, and Anaplasma species infecting sheep and goats. B. ovis is the most important disease agent. It is transmitted by Rhipicephalus bursa, R. turanicus, Hyalomma anatolicum excavatum, and probably by R. evertsi evertsi B. ovis is widely spread in southern Europe, the Middle East, and central Asia. Its geographical distribution in South and East Asia and in Africa is widely unknown. B. motasi obviously represents several nosodemes in separate regions. It is not pathogenic for intact sheep in northern Europe, whereas it is probably more pathogenic than B. ovis in India and northern Africa. The known vectors of B. motasi are Haemaphysalis punctata and R. bursa. Theileria hirci is transmitted by H. a. anatolicum but occurs outside the distribution area of this tick. Malignant theileriosis of sheep and goats is an important disease in Iraq, Iran, and India. An attenuated macroschizont vaccine is successfully being used in Iran. Anaplasma ovis is transmitted by R. bursa and probably other ticks in the Old World and by Dermacentor andersoni in the New World. A. ovis is widely spread in the Old World. Outbreaks occur only under extreme conditions. The identity of the tick-borne disease agents of sheep and goats and of their vector ticks is uncertain in many regions of the Old and the New World.
Anaplasmosis↗
Conventional vaccines for tick-borne haemoparasitic diseases of sheep and goats.
Of the many tick-borne haemoparasites of sheep and goats, three may be controlled by vaccination. A live virulent blood vaccine for Cowdria ruminantium infection (heartwater) is used widely in southern Africa in an infection and treatment procedure. A live vaccine for Babesia ovis attenuated by passage in splenectomised sheep has been used extensively in Bulgaria with good results. A live vaccine for Theileria hirci, consisting of schizonts propagated in a lymphoid cell culture and attenuated by passage, has been used successfully in the Middle East.
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Subunit vaccines for the control of tick-borne diseases: implications for the future.
Tick-borne parasites are a major constraint to the improvement of livestock productivity in the developing world. These parasites include Theileria parva, T. annulata, Babesia bigemina, B. bovis, Anaplasma marginale and Cowdria ruminantium. The impact of these diseases is currently limited by the use of acaricides to decrease transmission by the tick vectors and immunization of the host animals using live vaccines. The use of acaricide is hampered by the development of acaricide resistance and live vaccines are dependent on cold chain facilities, which are generally unreliable in developing countries. There is therefore a requirement for improved vaccines that circumvent these problems. Candidate vaccine antigens have been identified for most of these parasites and are currently being evaluated for their capacity to induce solid protection.
Anaplasma↗