An investigation on vertical transmission of Leishmania infantum in experimentally infected dogs and assessment of offspring's infectiousness potential by xenodiagnosis.

Dogs are the main reservoir host of Leishmania infantum, etiologic agent of human visceral leishmaniasis (HVL) and canine visceral leishmaniasis (CVL). Transmission of L. infantum to humans and dogs is mainly through the bite of infected sand flies. In the Western Mediterranean basin, Phlebotomus perniciosus is the main vector of L. infantum. However, occasional vertical transmission of L. infantum has been reported. This study investigated L. infantum vertical transmission in offspring of experimentally infected dogs. Among 14 surviving puppies from three female beagle dogs that developed CVL following an experimental infection with L. infantum, one was tested positive by indirect immunofluorescence antibody test, by PCR and by xenodiagnosis with a high parasite burden in the spleen at 14 months old. None of the remaining puppies were tested positive for L. infantum. These findings strongly suggest that infected puppies following vertical transmission can sustain infection and contribute in infecting sand flies with L. infantum. Any strategy for controlling CVL should take into consideration the vertical transmission of L. infantum.

Anaplasma phagocytophilum infection in American robins and gray catbirds: an assessment of reservoir competence and disease in captive wildlife.

Anaplasma phagocytophilum (Dumler et al.) is the bacterial agent of human granulocytic anaplasmosis, an emerging infectious disease. The main vector of A. phagocytophilum in the United States is the blacklegged tick (Ixodes scapularis (Say)) and various small and medium-sized mammals are reservoirs. Previous studies indicate that birds are exposed to A. phagocytophilum; however, because no studies have directly investigated avian susceptibility, reservoir competence, and morbidity for A. phagocytophilum, uncertainty remains as to what role birds could play in its transmission ecology. In a controlled laboratory study, we tested whether two species, the American robin (Turdus migratorius (L.)) and the gray catbird (Dumetella carolinensis (L.)), can become infected with and then transmit A. phagocytophilum to feeding ticks, and whether exposed birds develop disease. Wild caught, seronegative birds (n = 10 per species) were exposed to A. phagocytophilum-infected I. scapularis nymphs (day 0). Transmission was assessed by xenodiagnosis on days 7, 14, 42, and 77; blood was assayed for bacteremia and serology. A. phagocytophilum was detected using quantitative polymerase chain reaction targeting the 16s rRNA gene. One robin infected 2 of 13 larval ticks (15%) on day 7; no other birds were found to infect feeding ticks at any time. Birds did not develop bacteremia, specific antibodies or significant illness because of exposure. Mouse controls became bacteremic, infected feeding ticks, and seroconverted. Our results suggest that these two avian species are unlikely to play a significant role in the maintenance of the agent of human granulocytic anaplasmosis and that avian serosurveys may not be a reliable indicator of A. phagocytophilum exposure.

[Chronic Chagas' disease: from xenodiagnosis and hemoculture to polymerase chain reaction]. / Doença de Chagas crônica: do xenodiagnóstico e hemocultura à reação em cadeia da polimerase.

Although there has been an improvement in the diagnosis of chronic Chagas' disease, the low sensitivity of indirect parasitological tests is a drawback to its application in diagnosis and post-therapeutic control. Polymerase chain reaction (PCR) has limited use in routine diagnosis due to the need of specific laboratory facilities, common DNA cross-contamination, and high costs. At the same time, the high variability of PCR results found in different regions of Brazil raises some questions concerning its applicability for diagnosis. PCR's high specificity is indicative that it can be used as a confirmation method in inconclusive serology diagnosis as well as an auxiliary method in pos-therapeutic control of chronic Chagas' disease when comparing to serology and parasitological techniques. It is discussed here the applicability of molecular and indirect parasitological methods in the diagnosis and post-therapeutic control of chronic Chagas' disease based on the literature published from 1954 to 2001.