RESUMO
Venezuela is a country where human and canine leishmaniosis due to Leishmania infantum, Leishmania braziliensis and other Leishmania spp. is endemic. However, only limited data is available on canine Leishmania infection in Venezuela. The aim of this cross-sectional study was to evaluate the prevalence of Leishmania infection in dogs (n = 152) from the states of Lara (n = 91) and Yaracuy (n = 61) in Venezuela by means of serological and molecular methods. Physical examination was performed and blood samples were collected from all dogs. Serology for antibodies reactive with L. infantum and L. braziliensis antigens was assessed by the enzyme-linked immunosorbent assay (ELISA) and detection of Leishmania DNA from blood samples was evaluated by kinetoplast Leishmania real-time polymerase chain reaction (RT-PCR). In addition, Leishmania internal transcribed spacer (ITS-1) RT-PCR was performed on the samples positive by kinetoplast RT-PCR. The prevalence of Leishmania infection based on serological and/or molecular techniques was 11.8%. The seroprevalence for L. infantum and L. braziliensis antigens were 2.1% (3/144) and 8.3% (12/144), respectively. All dogs from the state of Yaracuy were serologically negative to L. infantum while 4.6% (4/86) of the dogs were reactive to L. braziliensis antigen. Fourteen percent (8/58) of the dogs from the state of Lara were positive to L. infantum and 5.2% (3/58) to L. braziliensis antigen. Three dogs were positive to both Leishmania spp. antigens. By RT-PCR, 6.5% (4/61) and 4.4% (4/91) of the dogs were positive for infection in the states of Lara and Yaracuy, respectively. The RT-PCR product of one dog from the state of Yaracuy was sequenced revealing a 100% identity with L. infantum. However, all RT-PCR positive dogs were seronegative to both Leishmania spp. antigens. In conclusion, the positivity for Leishmania spp. infections observed indicates that dogs are frequently infected by L. infantum, L. braziliensis or related Leishmania spp. in Venezuela.
Assuntos
Doenças do Cão/epidemiologia , Leishmania braziliensis/isolamento & purificação , Leishmania infantum/isolamento & purificação , Leishmaniose Cutânea/veterinária , Leishmaniose Visceral/veterinária , Animais , Estudos Transversais , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/parasitologia , Masculino , Prevalência , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Estudos Soroepidemiológicos , Venezuela/epidemiologiaRESUMO
Prevention of canine Leishmania infantum infection is critical to management of visceral leishmaniasis in people living in endemic areas of Brazil. A bill (PL 1738/11), currently under consideration, proposes to establish a national vaccination policy against canine leishmaniasis in Brazil. However, there is no solid scientific evidence supporting the idea that this could reduce transmission from infected vaccinated dogs to sand flies to a level that would significantly reduce the risk of L. infantum infection or visceral leishmaniasis in humans. Thus, we advocate that insecticide-impregnated collars should the first line protective measure for public health purposes and that vaccines are applied on a case-by-case, optional basis for individual dog protection.
Assuntos
Leishmania infantum/imunologia , Leishmaniose Visceral , Psychodidae/parasitologia , Piretrinas/administração & dosagem , Vacinação/veterinária , Administração Tópica , Animais , Brasil/epidemiologia , Doenças do Cão/prevenção & controle , Doenças do Cão/transmissão , Cães , Humanos , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/parasitologia , Inseticidas/administração & dosagem , Inseticidas/farmacologia , Vacinas contra Leishmaniose , Leishmaniose Visceral/prevenção & controle , Leishmaniose Visceral/transmissão , Leishmaniose Visceral/veterinária , Psychodidae/efeitos dos fármacos , Piretrinas/farmacologiaAssuntos
Doenças do Gato/diagnóstico , Leishmaniose Cutânea/veterinária , Animais , Antígenos de Protozoários/sangue , Doenças do Gato/epidemiologia , Doenças do Gato/imunologia , Doenças do Gato/parasitologia , Gatos , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Leishmania braziliensis/genética , Leishmania braziliensis/imunologia , Leishmania braziliensis/isolamento & purificação , Leishmania infantum/genética , Leishmania infantum/imunologia , Leishmania infantum/isolamento & purificação , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Animais de Estimação/parasitologia , Reação em Cadeia da Polimerase em Tempo Real , Venezuela/epidemiologiaRESUMO
Piroplasmids are tick-borne protozoan parasites that infect blood cells (erythrocytes, lymphocytes or other leukocytes) or endothelial cells of numerous wild and domestic vertebrates worldwide. They cause severe disease in livestock, dogs, cats, wild mammals and, occasionally, in humans. Piroplasmid infections are prevalent in wild carnivores worldwide although there is limited information about their clinical and epidemiological importance. There are currently nine recognized species of Babesia, two of Theileria, two of Cytauxzoon and one of Rangelia infecting captive and wild carnivores, including members of Canidae, Felidae, Mustelidae, Procyonidae, Ursidae, Viverridae, Hyaenidae and Herpestidae in the Americas, Eurasia and Africa. However, the number of piroplasmid species is likely higher than currently accepted due to the reported existence of DNA sequences that may correspond to new species and the lack of studies on many host species and biogeographical areas. Indeed, many species have been recognized in the last few years with the advancement of molecular analyses. Disease and mortality have been documented in some wild carnivores, whereas other species appear to act as natural, subclinical reservoirs. Various factors (e.g. unnatural hosts, stress due to captivity, habitat degradation, climate fluctuation or immunosuppression) have been associated with disease susceptibility to piroplasmid infections in some species in captivity. We aimed to review the current knowledge on the epidemiology of piroplasmid infections in wild carnivores and associated tick vectors. Emphasis is given to the role of wild carnivores as reservoirs of clinical piroplasmosis for domestic dogs and cats, and to the importance of piroplasmids as disease agents for endangered carnivores.
Assuntos
Animais Selvagens/parasitologia , Carnívoros/parasitologia , Piroplasmida/isolamento & purificação , Infecções por Protozoários/epidemiologia , Animais , Saúde GlobalRESUMO
BACKGROUND: In rural parts of Africa, dogs live in close association with humans and livestock, roam freely, and usually do not receive prophylactic measures. Thus, they are a source of infectious disease for humans and for wildlife such as protected carnivores. In 2011, an epidemiological study was carried out around three conservation areas in Uganda to detect the presence and determine the prevalence of vector-borne pathogens in rural dogs and associated ticks to evaluate the risk that these pathogens pose to humans and wildlife. METHODS: Serum samples (n = 105), blood smears (n = 43) and blood preserved on FTA cards (n = 38) and ticks (58 monospecific pools of Haemaphysalis leachi and Rhipicephalus praetextatus including 312 ticks from 52 dogs) were collected from dogs. Dog sera were tested by indirect immunofluorescence to detect the presence of antibodies against Rickettsia conorii and Ehrlichia canis. Antibodies against R. conorii were also examined by indirect enzyme immunoassay. Real time PCR for the detection of Rickettsia spp., Anaplasmataceae, Bartonella spp. and Babesia spp. was performed in DNA extracted from FTA cards and ticks. RESULTS: 99% of the dogs were seropositive to Rickettsia spp. and 29.5% to Ehrlichia spp. Molecular analyses revealed that 7.8% of the blood samples were infected with Babesia rossi, and all were negative for Rickettsia spp. and Ehrlichia spp. Ticks were infected with Rickettsia sp. (18.9%), including R. conorii and R. massiliae; Ehrlichia sp. (18.9%), including E. chaffeensis and Anaplasma platys; and B. rossi (1.7%). Bartonella spp. was not detected in any of the blood or tick samples. CONCLUSIONS: This study confirms the presence of previously undetected vector-borne pathogens of humans and animals in East Africa. We recommend that dog owners in rural Uganda be advised to protect their animals against ectoparasites to prevent the transmission of pathogens to humans and wildlife.
Assuntos
Doenças do Cão/epidemiologia , Ixodidae , Infestações por Carrapato/epidemiologia , Doenças Transmitidas por Carrapatos/epidemiologia , Anaplasma/genética , Anaplasma/isolamento & purificação , Animais , Babesia/genética , Babesia/isolamento & purificação , Bartonella/genética , Bartonella/isolamento & purificação , Sequência de Bases , Doenças do Cão/microbiologia , Doenças do Cão/parasitologia , Cães , Ehrlichia/imunologia , Ehrlichia/isolamento & purificação , Feminino , Humanos , Ixodidae/microbiologia , Ixodidae/parasitologia , Masculino , Dados de Sequência Molecular , Prevalência , Rickettsia/imunologia , Rickettsia/isolamento & purificação , Infestações por Carrapato/parasitologia , Infestações por Carrapato/prevenção & controle , Doenças Transmitidas por Carrapatos/microbiologia , Doenças Transmitidas por Carrapatos/parasitologia , Uganda/epidemiologiaRESUMO
Canine leishmaniosis is a potentially life-threatening disease which is spreading geographically in the Old and New Worlds, where different diagnostic procedures, treatments, and control strategies are currently in place. This Opinion article outlines the similarities and differences between canine leishmaniosis in the Old and New Worlds, with emphasis on South America and Europe. Finally, it calls the attention of veterinary and public health authorities to standardize and improve practices for diagnosing, treating, and preventing the disease.
Assuntos
Doenças do Cão/parasitologia , Leishmaniose/veterinária , Animais , Doenças do Cão/diagnóstico , Doenças do Cão/epidemiologia , Doenças do Cão/prevenção & controle , Cães , Europa (Continente)/epidemiologia , Interações Hospedeiro-Parasita , Insetos Vetores/fisiologia , Leishmania/genética , Leishmania/fisiologia , Leishmaniose/diagnóstico , Leishmaniose/epidemiologia , Leishmaniose/parasitologia , Leishmaniose/prevenção & controle , América do Sul/epidemiologiaRESUMO
Vaccination of dogs, the domestic reservoir of Leishmania infantum, is the best method for controlling zoonotic visceral leishmaniasis. This strategy would reduce the incidence of disease in both the canine and, indirectly, the human population. Different vaccination approaches have been investigated against canine leishmaniasis (CaL) but to date there is only one licensed vaccine against this disease in dogs, in Brazil. DNA immunization is a promising method for inducing both humoral and cellular immune responses against this parasitic disease. Here, we report the results of a multiantigenic plasmid DNA vaccine encoding KMPII, TRYP, LACK and GP63 L. infantum antigens against experimentally induced CaL. Twelve dogs were randomly assigned to two groups receiving, at a 15 days interval, either four doses of plasmid DNA or similar injections of PBS. After vaccination, dogs were intravenously challenged with 5 x 10(7) promastigotes of L. infantum. The vaccine showed to be safe and well-tolerated. Neither cellular immune response nor antibodies directed against whole Leishmania antigen were detected after immunization in vaccinated dogs, although anti-LACK-specific antibodies were sporadically detected in two vaccinated dogs before challenge, thus suggesting that antigens were indeed expressed. A delay in the development of detectable specific immune response and parasite multiplication in vaccinated dogs was observed after challenge. Nevertheless, the multiantigenic Leishmania DNA vaccine was unable to induce protection against parasite dissemination or disease. This study emphasizes the need to strengthen DNA vaccines in order to obtain effective immune responses in models other than the murine.