Vaccuuming method as a successful strategy in the diagnosis of active infestation by Pediculus humanus capitis.

Most human epidemiological and clinical studies use visual inspection of the hair and scalp to diagnose Pediculus humanus capitis , however this method has low sensitivity to diagnose active infestations (presence of nymphs and adult lice). Vacuuming the hair and scalp has been used as a diagnostic method, but there are no previous data comparing its effectiveness with visual inspection. The aim of this study was to determine the prevalence of overall infestation (nits and trophic stages), of active infestation by Pediculus humanus capitis , and to evaluate the effectiveness of vacuuming in comparison with the visual inspection. Visual inspection was performed by three examiners and vacuuming of the scalp by one investigator, with an adapted vacuum cleaner. A total of 166 children aged 4 to 10 years old were randomly selected from public schools in Southern Brazil. Considering the positive results obtained by both methods, the prevalence of overall infestation was 63.3%, whereas active infestation was 18.7%. The visual inspection was more effective on diagnosing overall infestation, however, its effectiveness to detect active infestation was lower, ranging from 0.6% (RR=3%, p<0.001) to 6.6% (RR=35%, p=0.001), depending on the number of examiners. The effectiveness of vacuuming to diagnose active infestation was higher than the one of visual inspection, with a prevalence rate of 16.3% (RR=87%, p=0.332). As presented in our study, the vacuuming method was 2.74 to 7.87 times most likely to detect active infestation, thus it could be adopted as a more accurate method to diagnose active pediculosis.

Trypanosoma cruzi vector infection rate is underestimated in some localities in the state of Bahia

Bahia was the last Brazilian state declared free of Chagas disease transmission by Triatoma infestans in 2006. The program designed to control vector transmission of Chagas is currently active, and all potential triatomines collected by the Bahia State Department of Health officials are most frequently diagnosed as negative for Trypanosoma cruzi when analyzed by the conventional parasitological direct method. The aim of the current study was to investigate whether triatomines from Bahia are free of T. cruzi infection using a more sensitive diagnostic methodology, namely the kinetoplastid-DNA polymerase chain reaction (kDNA-PCR). With the help of health officials, 51 triatomines were analyzed from peridomicile areas within the central north region of the state of Bahia. The majority (60.8%) were Triatoma brasiliensis, 29.4% were Triatoma pseudomaculata, and 9.8% were unidentified nymphs. Only one insect tested potentially positive for T. cruzi by the conventional parasitological direct method, and 31.4% were positive for T. cruzi DNA by kDNA-PCR. Almost half the infected insects (41.9%) were T. brasiliensis, a species with high potential for T. cruzi transmission. These results demonstrate that the number of infected triatomines with high transmission potential of T. cruzi may be greater than expected in four localities in the state of Bahia

High occurrence of Calodium hepaticum (syn. Capillaria hepatica) spurious infection in a village in the Atlantic Forest of southern Brazil

Calodium hepaticum (syn. Capillaria hepatica) is a nematode of the Capillariidae family that infects rodents and other mammals. In Brazil, human spurious infections of C. hepaticum have been detected in indigenous or rural communities from the Amazon Basin, but not in the southern states of the country. Here, we report the highest occurrence (13.5% of 37 residents) of C. hepaticum human spurious infection detected in Brazil and the first record in a southern region, Guaraqueçaba. The finding is explained by the area being located in the Atlantic Forest of the state of Paraná, surrounded by preserved forests and because the inhabitants consume the meat of wild mammals.

High occurrence of Calodium hepaticum (syn. Capillaria hepatica) spurious infection in a village in the Atlantic Forest of southern Brazil.

Calodium hepaticum (syn. Capillaria hepatica) is a nematode of the Capillariidae family that infects rodents and other mammals. In Brazil, human spurious infections of C. hepaticum have been detected in indigenous or rural communities from the Amazon Basin, but not in the southern states of the country. Here, we report the highest occurrence (13.5% of 37 residents) of C. hepaticum human spurious infection detected in Brazil and the first record in a southern region, Guaraqueçaba. The finding is explained by the area being located in the Atlantic Forest of the state of Paraná, surrounded by preserved forests and because the inhabitants consume the meat of wild mammals.

Expression and subcellular localization of kinetoplast-associated proteins in the different developmental stages of Trypanosoma cruzi.

BACKGROUND: The kinetoplast DNA (kDNA) of trypanosomatids consists of an unusual arrangement of circular molecules catenated into a single network. The diameter of the isolated kDNA network is similar to that of the entire cell. However, within the kinetoplast matrix, the kDNA is highly condensed. Studies in Crithidia fasciculata showed that kinetoplast-associated proteins (KAPs) are capable of condensing the kDNA network. However, little is known about the KAPs of Trypanosoma cruzi, a parasitic protozoon that shows distinct patterns of kDNA condensation during their complex morphogenetic development. In epimastigotes and amastigotes (replicating forms) the kDNA fibers are tightly packed into a disk-shaped kinetoplast, whereas trypomastigotes (non-replicating) present a more relaxed kDNA organization contained within a rounded structure. It is still unclear how the compact kinetoplast disk of epimastigotes is converted into a globular structure in the infective trypomastigotes. RESULTS: In this work, we have analyzed KAP coding genes in trypanosomatid genomes and cloned and expressed two kinetoplast-associated proteins in T. cruzi: TcKAP4 and TcKAP6. Such small basic proteins are expressed in all developmental stages of the parasite, although present a differential distribution within the kinetoplasts of epimastigote, amastigote and trypomastigote forms. CONCLUSION: Several features of TcKAPs, such as their small size, basic nature and similarity with KAPs of C. fasciculata, are consistent with a role in DNA charge neutralization and condensation. Additionally, the differential distribution of KAPs in the kinetoplasts of distinct developmental stages of the parasite, indicate that the kDNA rearrangement that takes place during the T. cruzi differentiation process is accompanied by TcKAPs redistribution.

Detection of Anaplasma marginale DNA in larvae of Boophilus microplus ticks by polymerase chain reaction.

Boophilus microplus larvae from two different sources were used for the detection of Anaplasma marginale DNA: larvae A, which were collected from a pasture of an endemic farm, and larvae B, which originated from engorged female ticks fed on calves with no clinical signs of disease and with low rickettsemia (approximately 0.01 to 1.0%). Larvae A were collected monthly, from January to May in 2001. Two hundred engorged female ticks fed on calves that provided larvae B were divided into groups of 10 and kept in a controlled environment at either 18 degrees C or 28 degrees C. Fifty larvae were used from each sample for DNA extraction, and 5 muL of DNA were submitted to amplification of the sequence of msp5 gene of A. marginale by polymerase chain reaction (PCR). Seven out of 50 samples of larvae A (14%) were positive for the presence of DNA of A. marginale showing amplified product of 457 bp. Ten out of 91 samples of larvae B (11%) kept at 18 degrees C were positive, and all larvae B at 28 degrees C were negative. Thus, this study confirmed the presence of A. marginale DNA in B. microplus larvae by PCR. The EcoRI restriction enzyme analysis confirmed the specificity of the amplicon, which resulted in two fragments: 265 bp and 192 bp. The sequencing analysis of the amplicon from larvae demonstrated 98% homology with the msp5 sequence from Florida A. marginale strain.