Isolation and identification of Babesia ovis in Extremadura (Spain)

Endemic instability of ovine babesiosis in Turkey: A country-wide sero-epidemiological study

Ovine babesiosis is an endemic tick-borne disease of small ruminants in the Middle East, European, and some African and Asian countries, including Turkey. This study assessed whether the endemic status of this disease was stable or instable, which is important for disease control efforts. For this aim, 4115 sheep blood samples were collected from 81 cities in the seven geographical regions of Turkey. The diagnosis of Babesia ovis was made using microscopic and serological techniques. Thin blood smears were prepared from anticoagulated venous blood. Serum samples were screened for specific antibodies using an enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFAT). Recombinant Babesia ovis secreted antigen 1 (rBoSA1) was used in the ELISA. The antigen slides used in the IFAT were prepared from the B. ovis-infected blood at a high level of parasitemia (5 %). The animals were divided into three groups according to their age: group I (one to six months), group II (6-12 months), and group III (older than one year). The endemic status of B. ovis was determined according to the inoculation rate (h value) calculations. Babesia spp. merozoites were observed in 40 (0.97 %) of the slides. Seropositivity rates were 29.89 % (1230/4115) and 49.16 % (2023/4115) by the ELISA and IFAT, respectively. According to the IFAT results, 31.7 %, 33.6 %, and 52.8 % of the animals were seropositive in groups I, II, and III, respectively. The inoculation rates of the animals indicated that the endemic status of ovine babesiosis was mostly instable throughout the country. Endemic stability was found only in group I from four regions (Central Anatolia, Eastern Anatolia, Aegean, and Mediterranean). Based on these results, the risk of clinical infection due to tick infestation was high when the maternal immunity and non-specific age resistance weakens or disappears. Thus, vaccination is needed to protect sheep against B. ovis infections in Turkey.

Detection of Babesia infection among human, goats and sheep using microscopic and molecular methods in the city of Kuhdasht in Lorestan Province, West of Iran

Babesiosis is a lethal protozoan disease, responsible for the loss of livestock in Iran and in the world. The purpose of the current study was to detect and identify Babesia spp. infection using microscopic and molecular methods in human, sheep and goats in Kuhdasht region, in the Lorestan Province, west of Iran. During 2013, a total of 384 blood smear samples were collected from 51 goats, 306 sheep suspected of Babesiosis infection and 27 humans from Kuhdasht region. The blood samples were fixed, stained and under light microscopic examined. DNA samples were extracted and amplified by polymerase chain reaction of 18S-rRNA gene. PCR and the semi-nested PCR were performed to identify to Babesi spp. and to differentiate genus of Theileria and Babesia spp. The results of microscopic examination indicated that a total of 47 (12.2%) samples were positive for Babesia spp. infection: 38 (9.9%) belonging to sheep and 9 to goats (2.3%). No Babesia was observed in human samples. The PCR showed a band size of 389 bp, of Babesia spp. and the semi-nested PCR detected B. ovis with a band size of 186 bp. By molecular method, 16 (4.2%) sheep and 2 (0.5%) goat blood samples were infected by Babesia. Totally, 18 samples (4.7%) were observed to have Babesia, while no infection was found in human. Thus, the results of our study have shown sheep and goats could be vulnerable to Babesia spp., especially B. ovis in Lorestan Province, Iran. Therefore, studies on the status of the animal Piroplasmosis especially Theileriosis are recommended.

Molecular detection of Babesia ovis in sheep and ticks using the gene encoding B. ovis surface protein D (BoSPD)

The gene encoding Babesia ovis surface protein D (BoSPD) was cloned from B. ovis cDNA library. This gene encodes a polypeptide chain of 155 amino acids, including a predicted 22 amino acid signal peptide. Sequence analysis of the BoSPD suggested that it is a surface protein with no known domains. BLAST analysis followed by multiple alignments showed four orthologs from other Apicomplexan species and suggested that BoSPD is specific for B. ovis. BoSPD-based PCR was then developed to specifically detect B. ovis in experimentally-infected sheep and Rhipicephalus bursa ticks, as well as in field samples. The PCR enabled detection of B. ovis at a calculated parasitemia of 0.0016% and was shown to be specific for B. ovis. Moreover, the BoSPD PCR allowed detection of prolonged subclinical infection in experimentally-infected lambs and in dissected organs of experimentally-infected ticks. Finally, the PCR was used to detect parasitemia in blood samples from naturally-infected sheep and in R. bursa ticks collected from sheep in an infected flock. These results suggest that the BoSPD gene sequence can be used as a specific and sensitive marker, allowing detection of subclinical parasitemia in sheep and in ticks. Based on its predicted properties, BoSPD may be considered as a candidate for anti-B. ovis vaccine development or a target for anti-B.ovis treatment.

PCR-Based Detection of Babesia ovis in Rhipicephalus bursa and Small Ruminants

This study aimed to assess the prevalence of Babesia ovis infection in adult Rhipicephalus bursa and small ruminants in West Azerbaijan province, Iran. Blood samples were collected from 280 sheep and 122 goats of forty randomly selected flocks. Specific B. ovis fragment was detected in 67 animals (16.7%), of which 52 animals (18.6%) were sheep and 15 animals (12.2%) goats (P < 0.05). Of the 848 R. bursa collected from naturally infested small ruminants and farm dogs, Babesia ovis was detected by PCR in salivary glands of 94 adult ticks. The frequency of B. ovis infection was higher in flocks with tick in comparison with animals without tick (P < 0.05). Positive amplification from blood of ruminants, ticks, oviposition ticks, eggs, and larvae was subjected to restriction digestion with HphI. One RFLP profile was produced. The PCR-RFLP results indicated that one strain of B. ovis exists in this area. The results showed that the PCR was useful method to investigate the epidemiology of small ruminants' babesiosis. Furthermore, R. Bursa, which can transovarially transmit B. ovis and as well as being widely distributed in West Azerbaijan province, Iran, might play an important role in the field as a natural vector of B. ovis.

Molecular studies on Babesia, Theileria and Hepatozoon in southern Europe. Part II. Phylogenetic analysis and evolutionary history

Following a study on molecular epizootiology of Hepatozoon canis and piroplasmids (Babesia spp. and Theileria spp.) in southern Europe, newly obtained sequences of 18s rRNA gene were used for phylogenetic analysis. Partial sequences were analysed in isolates showing high degree of homology (>99%) with previous GenBank entries: H. canis, B. canis vogeli, B. equi (two isolates, Spain1 and Spain2), T. annulata and Theileria sp. The complete gene sequences were used for B. ovis and B. bovis, that showed lower homology (<95%) with rapport to previously reported species or isolates. A first set of phylogenetic trees constructed with partial 18s rRNA sequences showed that most European isolates clustered unambiguously with previously described species, so that minor sequence dissimilarities found are due probably to strain variations. The second set of phylogenetic trees was made using the complete 18s rRNA sequences of 44 species from GenBank and the newly sequenced B. ovis and B. bovis. The analysis revealed for the first time a division of piroplasmids in five clades: (1) B. microti group, with B. rodhaini, B. felis, B. leo, B. microti and T. annae (proposed name for the group, without taxonomic value: Archaeopiroplasmids), (2) Western USA Theilerid-like group (proposed name: Prototheilerids), (3) Theileria group, containing all Theileria species from Bovinae (proposed name: Theilerids), (4) A first group of Babesia species including B. canis and B. gibsoni from canids together with B. divergens and B. odocoilei (proposed name: Babesids), (5) A second group composed mainly by Babesia species from ungulates: B. caballi, B. bigemina, B. ovis, B. bovis and Babesia sp. from cow (proposed name: Ungulibabesids). The bootstrap support obtained with several analytical procedures for this new dicotomy of Babesiidae was always very high. Taking into account the present phylogenetic analysis and additional paleogeographic, parasitological and zoological evidences, two hypothesis on the origin and evolution of piroplasmids groups are presented.

Molecular studies on Babesia, Theileria and Hepatozoon in southern Europe. Part I. Epizootiological aspects

Molecular epizootiology of piroplasmids (Babesia spp., Theileria spp.) and Hepatozoon canis was studied in mammals from southern Europe (mainly from Spain, but also from Portugal and France). Partial amplification and sequencing of the 18s rRNA gene was used for molecular diagnosis. In some particular cases (B. ovis and B. bovis) the complete 18s rRNA gene was sequenced. Blood samples were taken from domestic animals showing clinical symptoms: 10 dogs, 10 horses, 10 cows, 9 sheep and 1 goat. In addition, DNA samples were isolated from blood of 12 healthy dogs and from spleen of 10 wild red foxes (Vulpes vulpes). The results of the survey were the following: Piroplasmid infections: Approximately from 50 to 70% of wild or domestic mammals (symptomatic) were infected. Piroplasmids detected in ruminants were:COW: B. bovis, T. annulata and Theileria sp. (type C). Sheep and goat: B. ovis. Piroplasmids present in canids were: Babesia canis vogeli, Babesia canis canis, Theileria annae and B. equi. The only piroplasmid found in asymptomatic dogs was B. equi. Piroplasmids found in horse were: B. equi and B. canis canis.H. canis infections in canids: H. canis was absent of domestic dog samples, whereas all foxes studied were infected by this protozoa. Genetic analysis showed that most of piroplasmid and Hepatozoon isolates from southern Europe matched unambigously with previously described species, as demonstrated by the high level sequence identity between them, usually between 99 and 100%. Minor differences, usually detected in hypervariable regions of 18s rRNA gene are probably due to strain variations or rare genetic polymorphisms. A possible exception was B. bovis, which shows a relatively lower degree of homology (94%) with regard to other B. bovis isolates from several countries. The same is true for B. ovis, that showed a 94% identity with regard to Babesia sp. from South African cow and a 92% with rapport to B. bovis from Portugal.

An epidemiological study on ovine babesiosis in the Mashhad suburb area, province of Khorasan, Iran

The prevalence of Babesia spp. infection was studied in sheep of the Mashhad area in Iran from 1998 to 2000. A total of 677 sheep originating from 115 flocks were clinically examined and investigated for the presence of Babesia spp. in appropriate blood smears and any tick species on the body of the animals. The study revealed that the infection rate for Babesia ovis and Babesia motasi were 167 (24.6%) and 4 (0.5%), respectively. Double (mixed) infections occurred in 21 (3%) sheep. Differences in infection rates were statistically non-significant between male and female sheep and between different age groups. Seasonally, the prevalence of Babesia spp. infection started to increase in April and reached highest values in August (56%), while a decrease was observed in September, reaching the lowest levels In February and March. The study demonstrated that 1.7% of sheep infected with B. ovis and 50% of sheep infected with B. motasi exhibited clinical signs. Sheep infected with B. motasi showed the highest levels of parasitemia. We found that 550 (73%) of the animals harbored Rhipicephalus sanguineus; 166 (21%) Hyalomma marginatum; 19 (2.5%) Dermacentor daghestanicus; 14 (1.8%) Hyalomma anatolicum; 6 (0.66%) Hyalomma asiaticum; and one (0.13%) Haemaphysalis punctata. The examination of 727 tick haemolymph samples and 52 tick egg smears showed that one sample (0.2%) of haemolymph of R. sanguineus, two (1.2%) haemolymphs of H. marginatum and two (2%) eggs of R. sanguineus harbored kinetes morphologically matching the criteria described for B. ovis.

Seroprevalence of Babesia ovis in sheep in Catalonia, northeastern Spain

An indirect fluorescent antibody test (IFAT) was developed in order to detect antibodies against Babesia ovis in different sheep flocks from Catalonia, northeastern Spain. Of the total 2174 sera included in the study, 133 (6.1%) were positive. Considerable differences in seroprevalence were detected depending on the geographical areas from which the animals originated. This must have been a consequence of the presence or absence of the vector tick, Rhipicephalus bursa, the distribution of which depends upon the bioclimate and vegetation present in the different areas studied. Even within those areas which afford suitable conditions for the presence of Rh. bursa ticks, and therefore in which positive titres were found, great differences in seroprevalence were detected among different flocks.

Seroprevalence of Babesia ovis in Spanish ibex (Capra pyrenaica) in Catalonia, northeastern Spain

A serologic survey was carried out in order to detect antibodies against Babesia ovis in a large population of Spanish ibex (Capra pyrenaica) from a hunting reserve in Catalonia, northeastern Spain. For this purpose, an indirect fluorescent antibody test (IFAT) was developed using a B. ovis isolate of ovine origin as antigen. Of the total 475 sera tested, 155 (32.6%) showed titres between 1:160 and 1:1280 and were considered positive. These results reveal that exposure of Spanish ibex to B. ovis is common in the studied area. No significant differences could be detected when comparing season or year of capture and age or sex of the animals in positive and negative samples. A high proportion of low titres was found in comparison to those reported by other researchers in sheep in Spain; this could be a consequence of the existence of some minor antigenic differences between B. ovis of domestic sheep and that found in Spanish ibex.