Genetic diversity among Babesia rossi detected in naturally infected dogs in Abeokuta, Nigeria, based on 18S rRNA gene sequences

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

A shared pathogen: Babesia rossi in domestic dogs, black-backed jackals (Canis mesomelas) and African wild dogs (Lycaon pictus) in South Africa

In sub-Saharan Africa, babesiosis in domestic dogs is caused primarily by Babesia rossi. Black-backed jackals (Canis mesomelas), which are subclinical carriers of B. rossi, were a likely reservoir host from which infection passed to domestic dogs. The role of other indigenous canids, e.g. African wild dogs (Lycaon pictus), as reservoirs of B. rossi has not been elucidated. The question also arises whether genetic differences have arisen between B. rossi infecting domestic dogs and "ancestral" B. rossi in jackals. In a previous study we found that nearly one-third (27 of 91) of jackals were infected with B. rossi; this was confirmed by 18S rDNA sequence analysis. In this study, the near full-length B. rossi 18S rRNA gene was successfully amplified from 6 domestic dogs and 3 black-backed jackals. The obtained recombinant sequences were identical (100 %) to previously described B. rossi sequences of black-backed jackals in South Africa, and 99 % similar to B. rossi from dogs in South Africa and the Sudan. Although blood specimens from 5 (10 %) of 52 free-ranging African wild dogs (from Kruger National Park, South Africa, reacted with the B. rossi probe on RLB hybridisation, the presence of B. rossi could not be confirmed by amplification and sequencing, nor by multiplex, real-time PCR. Although African wild dogs they can be infected with B. rossi without showing clinical signs, our findings suggest that they are apparently not important reservoir hosts of B. rossi.

Prevalence of canine babesiosis and their risk factors among asymptomatic dogs in the federal capital territory, Abuja, Nigeria

Babesia sp. are intracellular parasitic organisms that affects mainly the red blood cells of most mammals, causing the disease known as babesiosis, and transmitted by ticks. Babesisosis is potentially fatal and a major disease of dogs in Nigeria. Therefore, active and routine surveillance is recommended. In this study, the infection was investigated among apparently healthy domestic dogs in six Area Councils of the Federal Capital Territory (FCT), Abuja, Nigeria with the aim of determining the prevalence of the infection and the associated risk factors. Blood samples were collected from dogs (n = 480) at randomly selected households, from September 2015 to August 2016. Data regarding sampling location, sex, age, breed, use, presence or absence of ticks were recorded. Blood smears were prepared, stained with Geimsa stain, and examined under light microscope for Babesia sp. The results showed an overall prevalence of 10.8% Babesia canis infection. The prevalence among dogs examined in the six Area Councils were 6.3%, 12.5%, 10.0%, 12.5%, 11.3%, and 12.5 % for Abaji, AMAC, Bwari, Gwagwalada, Kuje and Kwali Area Council, respectively. The prevalence was highest (12.5%) among dogs from Kwali, AMAC and Gwagwalada, and lowest 5 (6.3%) among dogs from Abaji. Of the infected dogs, 13.7% were females and 8.3%, males. Dogs between 12 < 36 months old had the highest (17.0%) prevalence of infection while those of >60 months of age had the lowest (4.5%). Based on breed, the infection was more prevalent among exotic dogs (12.9%) than cross breeds (9.4%). While none of pet dogs were positive for Babesia canis, prevalence of 11.1% and 11.3% were recorded for guard and hunting dogs, respectively. Tick infestation was recorded for 254 dogs of which 17.3% had Babesia canis while only 3.5% of 226 non-infested dogs were Babesia positive. Babesia infection during the rainy season was 14.6% while 3.5% of dogs were positive during dry season. The data on monthly prevalence showed that August and September had the highest (13.5%) prevalence while January and February had the lowest (2.0%). We conclude that the canine babesiosis in the FCT was significantly dependent on age, use of dogs, tick infestation, and season. Therefore, priorities should be given to these factors while instituting control measures against the infection.

Long-term follow-up of owned, free-roaming dogs in South Africa naturally exposed to Babesia rossi

Babesia rossi is an important, tick-borne intraerythrocytic protozoan parasite; however, its natural history and epidemiology is poorly understood. Babesia rossi is the most virulent Babesia sp. in domestic dogs and is generally considered to cause severe babesiosis, which is fatal if left untreated. However, subclinical infections and mild disease from B. rossi have been reported, although the clinical progression of these cases was not reported. Therefore, to better understand B. rossi under field conditions, we evaluated its clinical progression and seroprevalence in an owned, free-roaming dog population in Zenzele, South Africa, where the parasite is endemic and prevention is not routine. The entire dog population in Zenzele was monitored intensively at the individual level from March 2008 until April 2014, primarily for a longitudinal study on rabies control. Subsequent evaluation of B. rossi comprised analyses of clinical and laboratory data collected from the Zenzele dog population during the 6 year study period. A substantial proportion (31% (n = 34)) of 109 dogs (randomly selected from every available dog in February/March 2010 older than ~6-8 weeks (n = 246)) tested by Indirect Fluorescent Antibody Test had seroconverted strongly to B. rossi. All 34 dogs were generally consistently healthy adults, determined from regular clinical examinations between March 2008 and April 2014. Blood smear examinations at multiple time points between July 2009 and February 2011 were also undertaken for almost all of these (34) seropositive dogs and all those tested were consistently negative for Babesia spp. Subclinical infections and mild disease were also the main findings for a separate group of 18 dogs positive for Babesia spp. on blood smear examination and confirmed to be infected with B. rossi by Polymerase Chain Reaction - Reverse Line Blot. Almost all of these dogs were positive at only one time point from repeat blood smear examinations between July 2009 and February 2011. We suggest that these observations are consistent with immunity acquired from repeated, low-level exposure to the parasite, generating transient subclinical infections or mild disease. Should this be the case, the use of tick control, particularly in adult dogs in free-roaming populations in B. rossi endemic regions, should be carefully considered.

Canine babesiosis in a male Boerboel: Hematobiochemical and anatomic pathological changes in the cardiorespiratory and reproductive organs

A 9-month old male Boerboel was presented at the University of Abuja Small Animal Clinic with a primary complaint of inappetence and micturition with brownish-yellow urine. Physical examination revealed pale mucous membranes, enlarged pre-scapular lymph nodes, bilateral ocular discharges, pyrexia (41.2 °C), depression and the presence of ticks of the genus Rhipicephalus sanguineus on the body of the animal. History revealed that the dog was recently vaccinated against canine distemper, hepatitis, leptospirosis, parainfluenza, parvovirus (DHLPP) and rabies six days prior to the onset of clinical signs, and had been anorexic. Following clinical examination, blood and faecal samples were collected for biochemical and parasitological analyses, and the results revealed the presence of intraerythrocytic Babesia parasites, normocytic and normochromic anaemia with extensive cellular damage. However, during the course of the investigation, the dog died. With appropriate consent, a post-mortem examination was carried out. Diffuse oedema with interstitial pneumonia in the lung, focal haemorrhage with cellular infiltration in the heart and progressive necrosis of epithelial cells within the seminiferous tubules of the testicles were observed. Many of the observed clinicopathological alterations were consistent with complicated babesiosis. However, in the current case, some unique systemic complications such as testicular degeneration, which has not been previously observed in the Boerboel are discussed.

First Molecular Detection of Piroplasm Infection in Pet Dogs from Gansu, China

Babesiosis, the hemolytic disease caused by Babesia, which is a tick-transmitted obligate intraerythrocytic protozoan parasite. This disease is responsible for significant mortality and morbidity rates and enormous economic losses to the livestock industry in tropical and subtropical regions worldwide. In this study, blood samples were collected from 141 pet dogs from Gansu, China, and analyzed for Babesia or Theileria spp. infection using specific PCR and sequencing based on 18S rRNA gene fragments. The results indicated that 18S rRNA gene sequences from 11 samples were similar to the 18S rRNA gene sequences in Babesia canis vogeli (2) and Theileria sinensis (9). The total infected rates of B. canis vogeli and T. sinensis were 1.4% (2/141) and 6.4% (9/141), respectively. This represents the first molecular report of T. sinensis in dogs worldwide and of B. canis vogeli in dogs from Gansu province of China. Furthermore, the finding of T. sinensis in dogs may represent the common infection of this parasite occurring in Gansu.