Molecular detection of Hepatozoon felis in cats from Maio Island, Republic of Cape Verde and global distribution of feline hepatozoonosis.

BACKGROUND: Vector-borne diseases are emerging worldwide and have an important zoonotic relevance. In the last few years, the interest in vector-borne pathogens in cats has increased. However, studies on feline vector-borne pathogens on tropical islands are lacking. Islands differ from continental countries because they have an enclosed population of animals, with all year presence of the vectors and, most often, without vector control measures. This study focused on the molecular identification and phylogenetic analysis of vector-borne pathogens in autochthonous cats with a mixed indoor-outdoor lifestyle from Maio Island, Cape Verde archipelago. METHODS: Blood samples were collected from 80 asymptomatic cats, representing almost a quarter of the total cat population of the island. The presence of DNA of protozoa of the genus Hepatozoon and bacteria belonging to family Anaplasmataceae and to genus Bartonella was assessed by PCR and phylogenetic analysis was conducted. Statistical analysis was performed to identify risk factors associated with infection. For feline hepatozoonosis, a worldwide dataset of Hepatozoon felis sequences retrieved from mammal species and vectors along with Hepatozoon spp. sequences retrieved from felids was generated, phylogenetically analyzed and the geographical and host distribution was assessed. RESULTS: Hepatozoon felis genotype I was identified in 12 (15%) cats from Maio Island whereas none of the cats were PCR positive for the other pathogens tested. No significant association of H. felis infection with age, sex, location or presence of vectors was observed by statistical analysis in Cape Verde's cats. Phylogenetic analysis on the worldwide dataset of feline Hepatozoon sequences showed two significant distinct clades for H. felis genotype I and II. Different geographical distributions were assessed: H. felis genotype I was the only genotype found in Africa and has been reported worldwide, with the exception of Japan and Brazil where only H. felis genotype II has been reported. CONCLUSIONS: The identification of H. felis genotype I in cats in Maio Island highlights the need to further investigate the significance of H. felis genotypes and to clarify the epidemiological aspects of this infection.

Molecular detection of Anaplasma platys, Ehrlichia canis, Hepatozoon canis and Rickettsia monacensis in dogs from Maio Island of Cape Verde archipelago.

Tick-borne diseases are emerging worldwide and have an important zoonotic relevance. Dogs play an important role in the epidemiology of several zoonotic tick-borne pathogens acting as sentinels and/or reservoirs. This study focused on the molecular identification of tick-borne pathogens in blood samples of 153 autochthonous asymptomatic dogs in Maio Island, Cape Verde archipelago. Eighty-four (54.9%) dogs were positive for one or more pathogens. Fifty-five (35.9%) dogs were infected with Hepatozoon canis, 53 (34.6%) with Anaplasma platys, five (3.3%) with Ehrlichia canis and Rickettsia monacensis, an emerging human pathogen, was also identified in a single dog (0.7%). The former three pathogens cause important canine tick-borne diseases that are transmitted or potentially transmitted by Rhipicephalus sanguineus s.l., the only hard tick identified in Cape Verde. Furthermore, Wolbachia spp. was amplified from the blood of one dog. None of the dogs were positive for Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Midichloria mitochondrii, Bartonella spp., Babesia spp. or Theileria spp. Fifty-four (35.3%) animals showed single infections and 30 (19.6%) co-infections, with A. platys and H. canis co-infection being the most frequent (28 dogs, 18.3%). The frequency of E. canis infection was statistically different among age groups (P=0.017), being higher among dogs older than 4 years compared to younger dogs. Infection by A. platys was also statistically different among age groups (P=0.031), being higher in dogs younger than 2 years compared to older dogs. The statistical analyses showed no significant association of PCR positivity with gender or location. The frequency of tick-borne pathogens detected in dogs in Maio Island, including R. monacensis, highlights the need to improve diagnosis and control in order to prevent the risk of transmission of these pathogens among dogs and humans living in or travelling to this touristic island.

Buffy coat smear or Knott's test: which to choose for canine microfilaria screening in field studies?

BACKGROUND: In recent years, an increasing number of cases of canine dirofilariasis have been reported worldwide. However, the rate of infection in dogs is largely unknown in many remote areas, and the importance of field studies for determination of the prevalence of canine dirofilariasis in such areas is well recognized. The detection of microfilariae by the modified Knott's test (MKT) is a recommended screening method for canine dirofilariasis. OBJECTIVES: The purposes of this study were to compare the diagnostic sensitivity of the MKT with the buffy coat smear method (BCS), and to evaluate the utility of these 2 methods under field study conditions. METHODS: One hundred and fifty dogs of the Maio Island of Republic of Cabo Verde, were screened for microfilariae using MKT and BCS. The results of the 2 methods were generated in a blinded manner and statistically compared. RESULTS: The detection rate was 4.67% with the MKT and 5.33% with BCS, which is statistically not different. The latter allowed a morphologic identification of Dirofilaria repens (later confirmed by molecular biology methods) and an estimation of parasite load, which varied from 15 to 185 microfilariae/mL. CONCLUSIONS: The methods MKT and BCS were comparable in terms of diagnostic sensitivity. However, the BCS was technically less demanding and produced permanent preparations, in which co-infection with other hematologic pathogens can easily be assessed. Overall, this method is well suited to assess microfilariae in a large number of animals, and it could replace the MKT in studies devoted to dirofilariasis.