Bionomics of Culex quinquefasciatus within urban areas of Rio de Janeiro, Southeastern Brazil

OBJECTIVE: To evaluate density, parity rates, daily survival and longevity of natural populations of Culex quinquefasciatus in three neighborhoods with distinct socio-economic and infrastructure profiles. METHODS: Mosquito collections of the Culex quinquefasciatus species were performed weekly during two four month periods, from August to November 2008 (spring) and March to June 2009 (fall), in a favela (slum), a suburban area and a middle class area of Rio de Janeiro, Southeastern Brazil. Collections were performed with backpack aspirators, in 20 randomly selected houses in each area per week, during 15-20 minutes per house. Ovaries were removed from captured females and classified as initial, intermediary or final stage. Furthermore, females were dissected for determination of parity based on the condition of the tracheal system. Mosquito survival rate and longevity were estimated on a per month basis for each neighborhood. RESULTS: We collected a total of 2,062 Culex quinquefasciatus, but monthly vector density was not correlated with temperature and rainfall. We dissected the ovaries of 625 Culex quinquefasciatus, and overall, there was a higher proportion of nulliparous females during the dryer months, while gravid females were more frequent in rainy months. In the middle class neighborhood, the parity rate reached up to 93.75% with survivorship of 0.979. Lower parity and survival rates were obtained in the suburban area (as low as 36.4% parity and 0.711 daily survival). Up to 84.7% of Culex quinquefasciatus females could survive the eight day period needed to complete West Nile Virus incubation. CONCLUSIONS: The survival rate of Culex quinquefasciatus varied significantly between the neighborhoods. This suggests that vectorial capacity and disease transmission risk may vary greatly between different urban areas, which is potentially useful information for vector control programs

Occurrence of gastrointestinal parasites in goat kids Ocorrência de parasitos gastrintestinais em cabritos

Fecal samples from male and female goat kids, of different breeds and up to one year of age, were analyzed to determine egg and oocyst counts per gram of feces (EPG and OPG, respectively), and fecal culturing was performed to identify nematode genera. Helminth eggs and Eimeria spp. oocysts were found in 93.06% (188/202) and 77.22% (156/202) of the fecal samples, respectively. From fecal cultures, the following genera were identified: Cooperia in 11.88% (24/202), Haemonchus in 51.98% (105/202), Oesophagostomum in 9.4% (19/202), Strongyloides in 5.94 (12/202) and Trichostrongylus in 20.79% (42/202) of the samples. The Eimeria species found were E. alijevi in 25.24% (51/202), E. arloingi in 7.42% (15/202), E. caprina in 2.97% (6/202), E. caprovina in 10.39% (21/202), E. christenseni in 4.45% (9/202), E. joklchijevi in 11.38% (23/202), E. hirci in 9.4% (19/202) and E. ninakohlyakimovae in 28.71% (58/202) samples. Among the gastrointestinal parasites, the genus Haemonchus and two Eimeria species (E. ninakohlyakimovae and E. alijevi) were predominants.<br>Amostras fecais de cabritos machos e fêmeas, de diferentes raças e com até uma ano de idade, foram examinadas para determinação do número de ovos e oocistos por grama de fezes (OPG e OoPG, respectivamente) e coprocultura para identificação genérica dos nematódeos. Ovos de helmintos e oocistos de Eimeria spp. foram observados em 93,06% (188/202) e 77,22% (156/202) das amostras, respectivamente. Pelas coproculturas, foram identificados os gêneros Cooperia em 11,88% (24/202), Haemonchus em 51,98% (105/202), Oesophagostomum em 9,4% (19/202), Strongyloides em 5,94 (12/202) e Trichostrongylus em 20,79% (42/202) das amostras. As espécies de Eimeria encontradas foram E. alijevi em 25,24% (51/202), E. arloingi em 7,42% (15/202), E. caprina em 2,97% (6/202), E. caprovina em 10,39% (21/202), E. christenseni em 4,45% (9/202), E. joklchijevi em 11,38% (23/202), E. hirci em 9,4% (19/202) e E. ninakohlyakimovae em 28,71% (58/202) das amostras. Dentre os parasitas gastrintestinais, houve predominância do gênero Haemonchus e de duas espécies de Eimeria: E. ninakohlyakimovae e E. alijevi