Fabiana Lessa Silva

Venereal transmission of canine visceral leishmaniasis

Leishmania chagasi, the agent of visceral leishmaniasis in dogs in the Americas has a tropism to the male genital system, particularly the epididymis, prepuce, and glans penis, resulting in shedding of Leishmania in the semen. The goal of this study was to verify the possibility of venereal transmission of L. chagasi. Twelve Leishmania-free bitches, housed in the absence of the insect vector, copulated with multiple naturally infected dogs that were shedding Leishmania in the semen. PCR analysis of serially collected ejaculates indicated that shedding of Leishmania in the semen is intermittent. Three bitches seroconverted, and six were PCR positive by the end of the experimental period (165 days after the last copulation). These data support the notion that L. chagasi may be sexually transmitted from naturally infected dogs to susceptible bitches in the absence of the biological insect vector.

Visceral leishmaniasis in captive wild canids in Brazil

Visceral leishmaniasis (VL) is endemic in Belo Horizonte (State of Minas Gerais, Brazil). Leishmania sp. can naturally infect several species of mammals, and the domestic dog is the most important reservoir of the disease in South America. This report describes five cases of visceral leishmaniasis in Brazilian canids. Among 15 animals kept in captivity in a zoo in Belo Horizonte (State of Minas Gerais, Brazil), two animals, a bush dog (Spheotos venaticos) and a hoary zorro (Lycalopex vetulus) were serologically positive and developed clinical signs of VL, whereas three other canids, including a crab-eating fox (Cerdocyon thous), a maned wolf (Chrysocyon brachyurus), and a hoary zorro (Lycalopex vetulus) had positive serological results without clinical signs.

Modulation of the Bovine Trophoblastic Innate Immune Response by Brucella abortus

ABSTRACT Brucellosis is still a widespread zoonotic disease. Very little is known about the interaction between Brucella abortus and trophoblastic cells, which is essential for better understanding the pathogenesis of the Brucella-induced placentitis and abortion, a key event for transmission of the disease. The goal of this study was to evaluate the profile of gene expression by bovine trophoblastic cells during infection with B. abortus. Explants of chorioallantoic membranes were inoculated with B. abortus strain 2308. Microarray analysis was performed at 4 h after infection, and expression of cytokines and chemokines by trophoblastic cells was assessed by real-time reverse transcription-PCR at 6 and 12 h after inoculation. In addition, cytokine and chemokine expression in placentomes from experimentally infected cows was evaluated. Expression of proinflammatory genes by trophoblastic cells was suppressed at 4 h after inoculation, whereas a significant upregulation of CXC chemokines, namely, CXCL6 (GCP-2) and CXCL8 (interleukin 8), was observed at 12 but not at 6 h after inoculation. Placentomes of experimentally infected cows had a similar profile of chemokine expression, with upregulation of CXCL6 and CXCL8. Our data indicate that B. abortus modulates the innate immune response by trophoblastic cells, suppressing the expression of proinflammatory mediators during the early stages of infection that is followed by a delayed and mild expression of proinflammatory chemokines, which is similar to the profile of chemokine expression in the placentomes of experimentally infected cows. This trophoblastic response is likely to contribute to the pathogenesis of B. abortus-induced placentitis.

Quails are resistant to infection with Neospora caninum tachyzoites

Abstract The aim of this study was to characterize the role of quails (Coturnix coturnix japonica) as intermediate hosts for Neospora caninum. Fifty-eight 20-day old quails were individually identified with numbered rings and kept in cages adequate for the species. The birds were fed commercial feed and distilled water ad libitum. They were weighed daily during the first month and every seven days from then on. The birds were randomly distributed into 3 groups; 40 quails (group A) and 8 quails (group B) received 3.5×106 and 5×106 N. caninum tachyzoites, respectively, and 10 quails (group C) received placebo. Four quails from group A and one from group C had their blood collected and were euthanized on the 1st, 3rd, 5th, 7th, 14th, 21th, 30th, 60th, 120th day after infection (DAI), and 4 quails from group B were euthanized on days 60th and 120th DAI. Following euthanasia, the birds were submitted to necropsy, the organs were weighed and fragments were collected for histopathology, immunohistochemistry (IHC) and PCR. On the 60th DAI, two dogs were fed tissue obtained from group A quails, and one dog was fed quail tissues from group B. The dogs’ blood was collected weekly for serology, and their feces were collected daily for 33 days for microscopy and molecular identification of oocysts. Students t-test was used to compare the weights of the collected organs and the quail and cloacal temperature. No quail presented any clinical signs or died. Splenomegaly and hepatomegaly were the primary necropsy findings during the first week of infection (p <0.05). Positive serology, immunoreactivity through IHC and molecular identification of the parasite, were observed, especially during the first two weeks of infection. No dogs eliminated the oocysts or seroconverted. The infected quails gained more weight than the control quails. The results demonstrated that quails are resistant to infection with N. caninum tachyzoites under the conditions of this study.

Epidemiology of canine leishmaniasis in southern Bahia, Brazil.

Leishmaniosis is a zoonosis caused by protozoa of the genus Leishmania. American cutaneous leishmaniosis (ACL) is mainly caused by the species L. amazonensis and L. braziliensis, and American visceral leishmaniosis (AVL) is caused by L. infantum chagasi. In addition to their proven roles as reservoirs of AVL, dogs are also suspected by researchers to be reservoirs of ACL due to reports of this infection in domestic environments and of infected dogs in endemic areas. The aim of this study was to detect Leishmania sp. infection in dogs from Vila Operária, Buerarema, Bahia, using parasitological tests, indirect immunofluorescent assay (IFA) and polymerase chain reaction (PCR). Furthermore, this study also aimed to identify risk factors associated with illness in dogs in this locality by conducting an epidemiological survey. For this purpose, 292 dogs were clinically evaluated for the presence of skin lesions, and the dogs that showed these changes were submitted to scarification injury to enable preparation of slides for microscopic study of amastigotes. Subsequently, the dogs underwent blood sampling for serological (IFA) and molecular (PCR) tests. Additionally, the owners of the dogs answered an epidemiological questionnaire to facilitate the identification of risk factors for exposure of dogs to pathogens of ACL. Of the 292 dogs studied, 13 (4.5%) had lesions suggestive of ACL, but with a negative parasitological examination and 147 (50.3%) were seropositive according to the IFA. Of the 273 dogs studied using PCR test, 10 (3.66%) were positive for L. braziliensis, and all samples were negative for L. infantum chagasi. Wastelands in the peridomicile and the presence of light in the household were risk factors associated with ACL. The results show that Vila Operária has asymptomatic dogs with ACL and that the detection sensitivity of the IFA was higher than that of PCR for the infected dogs.

Diagnosis and epidemiology of canine leishmaniasis in southeastern Bahia, Brazil.

Leishmaniasis is a disease caused by protozoa of the genus Leishmania. Two distinct forms are recognized: visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). In the Americas, the causative agent of VL is L. infantum chagasi, whereas L. braziliensis is principally responsible for CL. Domestic dogs constitute the main source of VL in urban environments, and have also been implicated in CL epidemiology. We carried out molecular and serological surveys to detect Leishmania infection in dogs from the municipality of Ituberá in Bahia, Brazil. Furthermore, we identified risk factors associated with illness in dogs from this locality. Blood samples were collected from 399 dogs and tested using an indirect immunofluorescence assay (IFA) and polymerase chain reaction (PCR) to detect Leishmania spp antibodies and L. infantum chagasi and L. braziliensis DNA, respectively. Dogs were clinically evaluated and tissue samples from those exhibiting skin lesions were examined for parasites. In addition, the dog owners completed an epidemiological questionnaire to identify factors associated with infection. Skin lesions consistent with CL were found on 37 (9.3%) of the evaluated animals, but parasitological examination was negative for all samples. The IFA returned positive results for 60 (15%) dogs. PCR identified DNA from L. braziliensis in 86 (21.6%) animals, where as all samples proved negative for L. infantum chagasi. The 134 dogs (33.6%) testing positive using IFA and/ or PCR were considered infected, and of these, only 13 demonstrated skin lesions. Animals from rural areas were 3.39-times more likely to be infected compared to those in urban environments.

Canine ehrlichiosis: prevalence and epidemiology in northeast Brazil

Ehrlichiosis is a zoonotic disease that is caused by bacteria of the genus Ehrlichia. The aims of this study were to detect the presence of Ehrlichia spp. in the blood of dogs in Ituberá, Bahia, and to compare the sensitivities and specificities of blood smear, serological, and molecular examinations. Furthermore, this study identified factors associated with exposure to the agent in dogs in this locality. Blood samples were collected from 379 dogs and submitted for indirect immunofluorescent assay and polymerase chain reaction testing for the detection of Ehrlichia spp. antibodies and DNA, respectively. Additionally, a peripheral blood smear was obtained from the ear tip for parasite identification. Of the 379 animals, 12.4%, 32.7%, and 25.6% were identified as positive on the blood smear, serological, and molecular tests, respectively. The dogs positive in one of the three techniques were considered exposed (46.9%). Younger dogs and rural habitat were protective factors and presence of ticks and contact with other dogs were the risk factors associated with exposure to the agent. It was concluded that dogs of Ituberá have high positivity for Ehrlichia spp. and that the diagnostic methods used for detection are complementary.

Canine hepatozoonosis in southeastern Bahia, Brazil.

In Brazil, canine hepatozoonosis is a tick-borne subclinical hemoparasitosis caused by a protozoa Hepatozoon canis and is highly prevalent in dogs in rural areas. An epizootiological study was conducted to investigate the prevalence of H. canis in the canine population of Ituberá, Bahia, and to analyze any associated risk factors. Blood samples were collected from 380 dogs and determined the presence of the protozoan by performing capillary blood smear and polymerase chain reaction (PCR). Epizootiological data were collected by asking dog owners to answer a structured questionnaire. H. canis gamonts were not detected in the blood smears. However, PCR detected H. canis in 163/380 (42.9%) dogs examined. Physical examination and anamnesis indicated 105 (64.4%) positive asymptomatic dogs. Hematological alterations were observed in 115 (70.5%) infected dogs. No clinical, hematological, or epizootiological variable was found to be significantly associated to the infection. In conclusion, the high prevalence of H. canis infection in local dogs may be because of the peri-urban features of this municipality. Moreover, to the best of our knowledge, this study the first study to report H. canis infection in the State of Bahia.

ULCERATIVE AND NECROTIZING GASTRITIS IN A CAPTIVE SLOTH (BRADYPUS VARIEGATUS, XENARTHRA, BRADYPODIDAE) DUE TO SEVERE PARASITISM WITH PARALEIURIS LOCCHII (NEMATODA, SPIROCERCIDAE)

Abstract This is the first reported case of lethal gastric parasitism by the nematode Paraleiuris locchii in a captive sloth (Bradypus variegatus). There were more than 600 parasites in the stomach of the sloth, associated with extensive areas of ulceration and necrosis. The animal developed emaciation, dehydration, and anemia that progressed to death.