Parasitological and serological studies on amoebiasis and other intestinal parasitic infections in the rural sector around Recife, Northeast Brazil

Parasitological examinations were carried out during July to December, 1989, on 485 inhabitants of four villages in São Lourenço da Mata, 25 km northwest of Recife, Pernambuco, Brazil. Approximately 99.6% of the inhabitants were infected with at least one species of intestinal parasites. A high prevalence of Schistosoma mansoni (82.1%), hookworm (80.2%) Trichuris trichiura (69.9%), Ascaris lumbricoides (61.9%) and Entamoeba coli (36.7%) infections were demonstrated. Test tube cultivation revealed that the most common species of hookworm in this region was Necator americanus (88.4%), and also that the prevalence of Strongyloides stercoralis was 5.8%. Three hundred and thirty-four sera were serologically examined for amoebiasis by the gel diffusion precipitation test (GDP) and enzyme-linked immunosorbent assay (ELISA). No positive reaction was observed in all sera as examined by GDP, while 24 sera were positive by ELISA.

Effect of wide spectrum anti-helminthic drugs upon Schistosoma mansoni experimentally infected mice

Mebendazole, albendazole, levamisole and thiabendazole are well known as active drugs against several nematode species, and against cestodes as well, when the first two drugs are considered. None of the drugs have proven activity, however, against trematodes. We tested the effect of these drugs on the fecal shedding of schistosome eggs and the recovering of adult schistosomes, after portal perfusion in Schistosoma mansoni experimentally infected mice. Balb/c mice infected with 80 S. mansoni cercariae were divided into three groups, each in turn subdivided into four other groups, for each tested drug. The first group was treated with each one of the studied drugs 25 days after S. mansoni infection; the second group was submitted to treatment with each one of the drugs 60 days after infection. Finally, the third group, considered as control, received no treatment. No effect upon fecal shedding of S. mansoni eggs and recovering of schistosomes after portal perfusion was observed when mice were treated with either mebendazole or albendazole. Mice treated with either levamisole or thiabendazole, on the other hand, showed a significant reduction in the recovering of adult schistosomes after portal perfusion, mainly when both drugs were given during the schistosomula evolution period, i.e., 25 days after cercariae penetration, probably due to unspecific immunomodulation

Neuroschistosomiasis due to Schistosoma mansoni: a review of pathogenesis, clinical syndromes and diagnostic approaches

Neuroschistosomiasis (NS) is the second most common form of presentation of infection by the trematode, Schistosoma mansoni. Granulomatous inflammatory reaction occurs as a result of schistosome eggs being transmitted to spinal cord or brain via the vascular system, or by inadvertent adult worm migration to these organs. The two main clinical syndromes are spinal cord neuroschistosomiasis (acute or subacute myelopathy) and localized cerebral or cerebellar neuroschistosomiasis (focal CNS impairment, seizures, increased intracranial pressure). Presumptive diagnosis of NS requires confirming the presence of S. mansoni infection by stool microscopy or rectal biopsy for trematode eggs, and serologic testing of blood and spinal fluid. The localized lesions are identified by signs and symptoms, and confirmed by imaging techniques (contrast myelography, CT and MRI). Algorithms are presented to allow a stepwise approach to diagnosis.

Approaches towards tick and tick-borne diseases control

Ticks are obligate haematophagous ectoparasites of wild and domestic animals as well as humans, considered to be second worldwide to mosquitoes as vectors of human diseases. Tick-borne diseases are responsible worldwide for great economic losses in terms of mortality and morbidity of livestock animals. This review concerns to the different tick and tick-parasites control methods having a major focus on vaccines. Control of tick infestations has been mainly based on the use of acaricides, a control measure with serious drawbacks, as responsible for the contamination of milk and meat products, as a selective factor for acaricide-resistant ticks and as an environmental contaminant. Research on alternatives to the use of acaricides is strongly represented by tick vaccines considered a more cost-effective and environmentally safe strategy. Vaccines based on the Bm86 tick antigen were used in the first commercially available cattle tick vaccines and showed good results in reducing tick numbers, affecting weight and reproductive performance of female ticks which resulted in reduction of cattle tick populations over time and consequently lower reduction of the pathogen agents they carry.

Polymerase chain reaction and nested-PCR approaches for detecting Cryptosporidium in water catchments of water treatment plants in Curitiba, State of Paraná, Brazil

Introduction Cryptosporidium is an important protozoan cause of waterborne disease worldwide of concern to public health authorities. To prevent outbreaks of cryptosporidiosis, the monitoring of this parasite in drinking water is necessary. In the present work, the polymerase chain reaction (PCR) and nested-PCR techniques were used to detect Cryptosporidium in raw water from catchment points of four water treatment plants (WTP) in Curitiba, Paraná, Brazil. Methods First, DNA extraction techniques were tested in samples containing decreasing amount of oocysts in reagent water, and PCR and nested-PCR with specific primers for 18SSU rDNA of Cryptosporidium were conducted to determine their sensitivity. In reagent water, a commercial extraction kit provided the best analytical sensitivity, and PCR and nested-PCR allowed the detection of five and two oocysts, respectively, with the primers XIAOR/XIAOF and XIAO1F/XIAO2R. Results In the spiking experiments, only the PCR with the primers AWA995F/AWA1206R was successful at detecting concentrations of 0.1 oocysts/mL. Two catchments samples of raw water and/or water sludge from four WTPs were contaminated with Cryptosporidium. Conclusions The application of the techniques to monitor Cryptosporidium in water and detect contamination in water catchments of WTPs in Curitiba are discussed in the present work.

Clinical and serological outcomes with different surgical approaches for human hepatic hydatidosis

ABSTRACTINTRODUCTION:Hydatidosis is the result of infection with the larval stages of some species of the genus Echinococcus. Treatment approaches for hydatid cysts include the use of albendazole, surgery, and/or medico-surgical procedures. The choice of the therapeutic surgical approach depends on the cyst number and localization, surgeon expertise, and presence of complications. The present study aimed to compare the outcomes of the following therapeutic approaches for the treatment of hepatic hydatid cysts: pericystectomy; the puncture, aspiration, injection, and reaspiration (PAIR) technique; and the PAIR technique followed by deroofing, evacuation of cysts, and omentoplasty.METHODS:The 54 patients were divided into 3 groups: Group I (14 patients) who underwent pericystectomy, Group II (23 patients) who underwent the PAIR technique, and Group III (17 patients) who underwent the PAIR technique followed by deroofing and omentoplasty. The diagnosis of hydatid cysts was based on serological testing using enzyme-linked immunosorbent assay, abdominal ultrasound, and parasitological examination of the cyst contents. Morbidity, mortality, length of hospital stay, recurrence, and postoperative complications were evaluated.RESULTS:Postoperative bleeding, infection, and recurrence were reported in Groups I and II; Group III did not experience postoperative infection and had shorter hospital stays. Recurrence and postoperative complications did not occur in Group III.CONCLUSIONS:The partial surgical procedure with deroofing, evacuation of the cysts, and omentoplasty, as performed in the present study, is recommended as a safe and effective method for elimination of the entire parasite with minimal possibility for intra-peritoneal spillage.

Two practical approaches to monitoring the zooplanktonic community at Lago Grande do Curuai, Pará, Brazil

The use of substitute groups in biomonitoring programs has been proposed to minimize the high financial costs and time for samples processing. The objectives of this study were to evaluate the correlation between (i) the spatial distribution among the major zooplankton groups (cladocerans, copepods, rotifers, and testaceans protozoa), (ii) the data of density and presence/absence of species, and (iii) the data of species, genera, and families from samples collected in the Lago Grande do Curuai, Pará, Brazil. A total of 55 sample of the zooplanktonic community was collected, with 28 samples obtained in March and 27 in September, 2013. The agreement between the different sets of data was assessed using Mantel and Procrustes tests. Our results indicated high correlations between genus level and species level and high correlations between presence/absence of species and abundance, regardless of the seasonal period. These results suggest that zooplankton community could be incorporated in a long-term monitoring program at relatively low financial and time costs.

Molecular biological approaches to the study of vectors in relation to malaria control

To a large extent, control of malaria vectors relies on the elimination of breeding sites and the application of chemical agents. There are increasing problems associated with the use of synthetic insecticides for vector control, including the evolution of resistance, the high cost of developing and registering new insecticides and an awareness of pollution from insecticide residues. These factors have stimulated interest in the application of molecular biology to the study of mosquito vectors of malaria; focussing primarily on two aspects. First, the improvement of existing control measures through the development of simplified DNA probe systems suitable for identification of vectors of malaria. The development of synthetic, non-radioactive DNA probes suitable for identification of species in the Anopheles gambiae complex is described with the aim of defining a simplified methodology wich is suitable for entomologist in the field. The second aspect to be considered is the development of completely novel strategies through the development of completely novel strategies through the genetic manipulation of insect vectors of malaria in order to alter their ability to transmit the disease. The major requirements for producing transgenic mosquitoes are outlined together with the progress wich has been made to date and discussed in relation to the prospects which this type of approach has for the future control of malaria.

Molecular approaches to malaria and Babesisosis diagnosis

The development of additional methods for detecting and identifuing Babesia and Plasmodium infections may be useful in disease monitoring, management and control efforts. To preliminarily evaluate sunthetic peptide-based serodiagnosis, a hydrophilic sequence (DDESEFDKEK)was selected from published BabR gene of B. bovis. Immunization of rabbits and cattle with the hemocyanin-conjugated peptide elicited antibody responses that specifically detected both P. falciparum and B. bovis antigens by immunofluorescence and Western blots. Using a dot-ELISA with this peptide, antisera from immunized and naturally-infected cattle, and immunized rodents, were specifically detected. Reactivity was weak and correlated with peptide immunization or infection. DNA-based detection using repetitive DNA was species-specific in dot-blot formats for B. bovis DNA, and in both dot-blot and in situ formats for P. falciparum; a streamlined enzymelinked synthetic DNA assay for P. falciparum detected 30 parasites/mm(cúbicos) from patient blood using either colorimetric (2-15 h color development) or chemiluminescent detection (0.5-6-min. exposures). Serodiagnostic and DNA hybridization methods may be complementary in the respective detection of both chronic and acute infections. However, recent improvements in the polymerase chain reaction (PCR) make feasible a more sensitive and uniform approach to the diagnosis of these and other infectious disease complexes, with appropriate primers and processing methods. An analysis of ribosomal DNA genes of Plasmodium and Toxoplasma identified Apicomplexa-conserved sequence regions. Specific and distinctive PCR profiles were obtained for primers spanning the internal transcribed spacer locus for each of several Plasmodium and Babesia species.