From the 143 samples, 13 were positive for Babesia canis species giving a prevalence of 9.0%, (95% C.I is 0.0437 to 0.1381). Out of the13 positive samples, 2 were positive for Babesia canis vogeli (1.4%; 95% CI: 0.0138 to 0.0142) which were assigned GenBank accession numbers, B.vogeli Nrb – MT740261, B.vogeliNrbB10 – MT740272.While 11 were positive for Babesia canis rossi (7.69%; 95% CI: 0.033 to 0.12),which were assigned the following GenBank accession numbers, B.rossi nvsa – MT740262,B.rossi NrbA1 – MT740263,B.rossi NrbB2 – MT740264,B.rossi NrbC3 – MT740265,B.rossi NrbD4 – MT740266,B.rossi NvsaB5 – MT740267,B.rossi NrbE6 – MT740268,B.rossi Msa7 – MT740269,B.rossi NrbF8 – MT740270,B.rossi NrbG9 – MT740271,B.rossi NrbB10 – MT740272,F12_BTH_F – MT740273
Table 3
Results with a breakdown for Babesia species detected, age, sex, and breed.
| | Sex | Breed | Age |
No. | M | F | L | E | J | A | O |
Babesia canis rossi | 11 | 6 | 5 | 9 | 2 | 3 | 7 | 1 |
Babesia canis vogeli | 2 | 1 | 1 | 2 | - | - | 2 | - |
Totals | 13 | 7 | 6 | 11 | 2 | 3 | 9 | 1 |
Totals as % | - | 53.85 | 46.15 | 84.61 | 15.38 | 23.08 | 69.23 | 7.69 |
*J-Juvenile (< 1 year), A-Adults (between 1–5 years), O-Older (> 5 years), M-males, F-Females, L-Local breed, E-Exotic breed
Of the 13 positive 23.08% were juveniles < 1 year old, while 69.23% were adult animals > 1 year ≤ 5 years old and 7.69% were older dogs ˃ 5 years old.
Of the 13 positive individuals, 53.85%were males and 46.15% were females.
Table 4
Positive results with a breakdown of age, sex, breed and the county of origin
| | Age | Totals | Sex | Totals | Breed | Totals |
| | J | A | O | | M | F | | L | E | |
Nairobi | B.canis rossi | 2 | 5 | 1 | 8 | 5 | 3 | | 6 | 2 | 8 |
B.canis vogeli | - | 2 | - | 2 | 1 | 1 | | 2 | | 2 |
Naivasha | B.canis rossi | - | 2 | - | 2 | 1 | 1 | | 2 | - | 2 |
B.canis vogeli | - | - | - | - | - | - | | - | - | - |
Mombasa | B.canis rossi | - | 1 | - | 1 | - | 1 | | 1 | - | 1 |
B.canis vogeli | - | - | - | - | - | - | | - | - | - |
*J-Juvenile (< 1 year), A-Adults (between 1–5 years), O-Older (> 5 years), M-males and F-Females L-local breed, E-exotic breed |
Key
J | Juvenile | ≤ 1yr |
A | Adult | ˃ 1 year ≤ 5yrs |
O | Old | ˃ 5yrs |
M | Male | - |
F | Female | - |
E | Exotic breed | - |
L | Local breed | - |
Oyamada M et al (2005) determined the prevalence for B.canis vogeli and B.canis rossi in a study from South Sudan to be 9.0% which is comparable to the results from this study which was 9.09% (Table3,33). In both studies, the prevalence of B.vogeli was significantly lower than that of B. rossi.
Co-infections of Babesia species and Hepatozoon canis were detected in South Sudan with a prevalence of 3.4% compared to none from this study (33).
In Uganda, B.rossi was detected in dogs with a prevalence of 7.8% which compares well to the prevalence observed in Kenya. In contrast, B.vogeli was not detected in the Ugandan study (34).
In addition B.rossi was detected in a Zambian study at a prevalence of 8.0% which compares well to the findings from our study. Interestingly, B.gibsoni was as well detected in Zambia and there was a high level of co-infections of B.gibsoni and B.vogeli with a frequency of 59.7% (35).Babesia gibsoni is known to occur in Africa,(13)some reports indicate wide distribution on the continent (13),other studies point to a more limited regional occurrence (14, 53, 54).Using molecular studies, B.gibsoni has been detected in the following countries (35, 38, 53).Similar studies failed to detect B.gibsoni in the following countries (33, 34, 36, 39).Due to the high prevalence of the parasite in Zambia (35) and the fact that this country shares a border with a core East African state like Tanzania, it would seem probable that the parasite is present in the region and will eventually be detected. This Babesia species was not detected in our study.
In agreement with the findings from the Kenyan study, B.rossi and B.vogeli were detected in Nigeria (36). Both B.rossi and B.vogeli were detected at a lower prevalence compared to other studies in Africa at 2.0% and 0.3% respectively. In studies from African countries, B.vogeli had a prevalence ranging between 1.4–5.8%. (37, 38).One of the most important factors determining infection rates with canine babesiosis is presence of competent tick vectors (13).The authors in the Nigerian study speculated that the higher infection rate observed in some African countries was probably due to greater levels of infestation with tick vectors e.g. South Africa (39) and South Sudan (33). There are no reports on the rate of tick infestation of dogs in Nigeria. From a Namibian study, B.vogeli was detected but from only one sample which had initially been diagnosed microscopically (37).
From a similar Angolan study and in agreement with this study, B.vogeli was detected at a prevalence of 1.0%.In contrast, B.rossi was not detected, but B.gibsoni was identified at a prevalence of 1.0% as well (38)
In agreement with the Kenyan study, B.vogeli and B.rossi were detected from a South African study with the prevalence of B.vogeli at 1.58%. Also, co-infections for these two Babesia species was only observed in one sample. In contrast, B.rossi was detected at a much higher prevalence of 36.93% compared to this and other similar studies in Africa (39).
The query sequences obtained from this study, B.vogeliNrb and B.vogeliNrbB had a 99.0% percentage identity (P.I) to a B.vogeli sequence from a pet cat in China (42).
The two Babesia canis vogeli sequences detected, GenBank accession no’s MT740272.1 (B.vogeliNrbB) and MT740261.1 (B.vogeliNrb), on the phylogenetic tree clustered closely to each other and with B.vogeli sequences from Africa. B.vogeli from Nigeria AB303076.1 with a percent identity P.I of 98.89% (36), B.vogeli from Egypt MN625891.1 with percent identity of 99.42% (52).Other closely related sequences include B.vogeli from Japan AY077719.1 with P.I of 99.42% (51)
Eleven Babesia canis rossi sequences were detected in the study. They were detected from all the counties. On the phylogenetic tree, the Kenyan sequences clustered closely to each other and B.rossi sequences from the African continent. Of the Kenyan sequences, MT740273.1 (F12) appeared most different from the others with P.I ranging between 97.88% for MT740267.1 (Nvsa_B) to 99.39% for MT740262.1 (Nvsa).
Other B.rossi sequences closely related to the Kenyan sequences include KY463431.1 obtained from black-backed jackals in sub-Saharan Africa with a P.I of 99.52% (40), DQ111760.1 obtained from dogs in Sudan with a P.I of 99.52% (33), LC331056.1 obtained from dogs in Zambia with a P.I of 99.36% (50).