Ocorrência de Chlamydophila psittaci em pombos (Columba livia) na cidade de Salvador, Bahia / Occurrence of the pigeon Chlamydophila psittaci in pigeons (Columba livia) within the city of Salvador, Bahia

A existência de populações numerosas de pombos (Columba livia) em centros urbanos, em quase todo o mundo, tem se tornado um risco à saúde pública em vista das zoonoses que podem transmitir. A infecção por Chlamydophila psittaci foi avaliada em pombos que frequentam áreas públicas, como praças, ruas e pontos turísticos na cidade de Salvador, Bahia, por meio da PCR em amostras de fezes frescas, suabes cloacais e orofaríngeos. O estudo revelou uma frequência de infecção por C. psittaci de 11,7% (16/137) dos pombos, e oito dos 10 locais pesquisados apresentavam aves infectadas. A detecção de C. psittaci em amostras de cloaca e orofaringe foi maior (15,8% - 3/19) que em amostras de fezes frescas (11% - 13/118). Os resultados demonstram a ocorrência de infecção por C. psittaci em pombos que habitam as áreas públicas da cidade de Salvador e apontam para a necessária elaboração de medidas de controle e monitoramento das populações de pombos urbanos, bem como de ações voltadas à conscientização da sociedade sobre os riscos à saúde pública.

The existence of numerous pigeon (Columba livia) populations in urban centers, in most of the world, has become a public-health risk given the zoonoses they can transmit. Infection with Chlamydophila psittaci was evaluated in pigeons that frequent public areas, such as squares, streets and tourist sites in the city of Salvador, through PCR from fresh feces samples, cloacal swabs and oropharyngeals. The study revealed a frequency of infection with C. psittaci of 11.7% (16/137) in pigeons, and infected birds were found in eight of the ten locales researched. The detection of C. psittaci in samples of cloaca and oropharyngs was greater (15.8% - 3/19) than in the samples of fresh feces (11% - 13/118). The results show the occurrence of infection with C. psittaciem in pigeons that live in public areas in the city of Salvador and points to the necessity of elaborating control and monitoring measures for the populations of urban pigeons as well as developing actions that will raise society´s awareness of these risks to public health.

Risk factors associated with Chlamydia psittaci infection in psittacine birds.

Chlamydia psittaci is the aetiological agent of chlamydiosis in birds, especially Psittaciformes. The objective of the present study was to detect C. psittaci by means of semi-nested PCR among psittacine birds sold at pet markets and kept as pet birds in Salvador, Bahia, Brazil. Questionnaires were used to identify risk factors involved in the epidemiology of the disease. In addition, the management of birds and cages was observed at each location studied. The frequency of C. psittaci infection was 10.6% (33/311) in the psittacine birds studied. Birds kept in households were less frequently positive (3.4%; 5/148) than those at pet markets (17.2%; 28/163). Among the several factors analysed in the epidemiology of the disease, only population density (P = 0.001) and cage hygiene (P = 0.041) in birds at pet markets were significantly associated with C. psittaci infection. These results demonstrate the presence of C. psittaci infection in Psittaciformes kept as pets and held at pet markets in Salvador, Bahia, showing that this micro-organism is a public health concern. Control measures should be encouraged to prevent the spread of the agent among birds, as well as among employees and customers.

Cross-sectional serological study of canine Leishmania infection in Fortaleza, Ceará state, Brazil.

Visceral leishmaniasis (VL) is one of the most important reemerging parasitic disease in the world. The domestic dog is the main reservoir in urban environments. The aim of this work was to extend the knowledge on canine Leishmania infection in the city of Fortaleza in northeastern Brazil, identifying the risk factors inherent in dog susceptibility to the infection. Two populations were analyzed, domestic dogs from clinics and the Veterinary Hospital Unit of Ceará State University and stray dogs captured by the Center for Zoonosis Control in Fortaleza. Blood samples were collected and centrifuged and the sera were stored at -20 degrees C. ELISA, with soluble crude Leishmania chagasi antigens (LTCC - WDCM731) was used for diagnosis. A total of 1,381 samples were tested, 750 from domestic and 631 from stray dogs. The seroprevalence of canine VL was 21.4% (135/631) in stray dogs and 26.2% (197/750) in domestic dogs. The seroprevalence of Leishmania infection in the six administrative regions of the city (Secretarias Executivas Regionais, or SER) among stray dogs was highest in SER V, representing 31.4% of the cases, with large dogs more infected (27.7%). Among domestic dogs Leishmania infection was most prevalent in SER V (38.5%) and VI (37.6%). The dogs' age (1-6 years), large size, environment with dense vegetation and presence of clinical signs compatible with Leishmania infection were associated with the illness in domestic dogs. The frequency of the infection varied seasonally. The seroprevalence was greatest in July and December. These results confirm Fortaleza is an endemic area for canine VL and suggest some variables associated with increasing infection risk in dog populations.

Short report: seroprevalence of Taenia solium cysticercosis in pigs in Bahia State, northeastern Brazil.

To determine the prevalence and etiologic factors of Taenia solium cysticercosis in pigs in the state of Bahia, northeastern Brazil, we performed serological surveys in Salvador, the capital of the state, and in two local towns, Santo Amaro and Jequié. Residents raising free-roaming pigs in the study areas were randomly selected. Sera were obtained from the pigs and examined by the enzyme-linked immunoelectrotransfer blot assay (EITB). The prevalence of antibodies to T. solium was 4.4% (2 of 45) in Salvador, 3.2% (3 of 93) in Santo Amaro, and 23.5% (24 of 102) in Jequié. A significantly high seroprevalence in Jequié was associated with poor sanitary conditions, such as an open sewer system and no inspection process of pork before marketing.

Investigations on naturally occurring Trypanosoma evansi infections in horses, cattle, dogs and capybaras (Hydrochaeris hydrochaeris) in Pantanal de Poconé (Mato Grosso, Brazil).

The prevalence of Mal de Cadeiras--Portuguese for Trypanosoma (T.) evansi infections in horses--as well as the prevalence of T.evansi infections in cattle, dogs and free-ranging capybaras (Hydrochaeris hydrochaeris) was investigated in Pantanal de Poconé (Mato Grosso, Brazil). In 0.3, 8.6 and 8.0% of the horses, dogs and capybaras, respectively, infection was detected using standard parasitological methods. A seroprevalence of 4.1, 2.3, 7.1 and 22.0% was found in horses, cattle, dogs and capybaras, respectively, using an enzyme-linked immunosorbent assay for the detection of T.evansi antigen (Ag-ELISA), whereas 9.6, 4.2, 18.6 and 14.0% of the animals investigated were reactive in a T.evansi antibody (Ab-) ELISA. Positive ELISA results ('high responders') were identified using computer-assisted mixture analysis (C.A.MAN). Agglutinating antibodies were detected by the T.evansi card agglutination test for trypanosomiasis (CATT/T.evansi) in 14.6%, 1.3%, 15.7% and 22.0% of the horses, cattle, dogs and capybaras, respectively. A moderate but significant (kappa test; p < 0.05) agreement beyond chance level was observed between Ab-ELISA and CATT results but generally not between antibody and antigen detection tests. Therefore, in an attempt to maximize the information yield of the three serodiagnostic tests, their results were numerically scored (negative = 0, intermediate = 1, positive = 2) and added up to a total score (TS) which was considered indicative for infection when TS > or = 4 (results of the Ag-ELISA received double weight). Estimates of seroprevalence according to TS were 13.2, 4.7, 30.0 and 24.0% for horses, cattle, dogs and capybaras, respectively. Identical isoenzyme profiles, known as zymodeme 58 (T.evansi MCAN/BR/86/H), were found in all T.evansi stocks isolated in the study area (six from dogs, one from a horse and one from a capybara). From the results of this study it can be inferred that Mal de Cadeiras is endemic in Pantanal de Poconé. Although clinical and parasitological findings support the possible role of the capybara as a reservoir host of T.evansi, dogs and cattle--due to their close contact with horses--should rather be regarded as efficient reservoir hosts for Mal de Cadeiras in the study area.

Construction of an intrinsic cut-off value for the sero-epidemiological study of Trypanosoma evansi infections in a canine population in Brazil: a new approach towards an unbiased estimation of prevalence.

In the serodiagnosis of tropical infectious diseases, cut-off values are often established by using sera from individuals living under moderate climatic conditions, not exposed to the risk of infection (non-endemic controls). This approach guarantees the disease-free status of the individuals within that control group but leads to an assembly of samples which are not representative for the disease-free individuals of the target population (selection bias). Using data from an epidemiological study of Trypanosoma evansi infection in dogs, two alternative methods to construct cut-off values for a T. evansi antibody ELISA are described which are solely based on a distribution analysis of the data from the endemic animals. By cluster analysis these data could be divided into 'high', 'intermediate' and 'low responders'. High responders could also be identified by using the computer-assisted analysis of mixtures (C.A.MAN). Conventional cut-offs were calculated from a group of non-endemic individuals. A receiver operating characteristic (ROC) analysis was performed to demonstrate the impact of the choice of cut-offs on the test specificity and on the estimated seroprevalence among the endemic population. The data indicate that distribution analysis, especially the mixture analysis (C.A.MAN), are valuable tools for the unbiased estimation of seroprevalence when representative negative controls are not available.