Chlamydia trachomatis serotype A infections in the Amazon region of Brazil: prevalence, entry and dissemination

INTRODUCTION: Chlamydia infection is associated with debilitating human diseases including trachoma, pneumonia, coronary heart disease and urogenital diseases. Serotypes of C. trachomatis show a fair correlation with the group of diseases they cause, and their distribution follows a well-described geographic pattern. Serotype A, a trachoma-associated strain, is known for its limited dissemination in the Middle East and Northern Africa. However, knowledge on the spread of bacteria from the genus Chlamydia as well as the distribution of serotypes in Brazil is quite limited. METHODS: Blood samples of 1,710 individuals from ten human population groups in the Amazon region of Brazil were examined for antibodies to Chlamydia using indirect immunofluorescence and microimmunofluorescence assays. RESULTS: The prevalence of antibodies to Chlamydia ranged from 23.9% (Wayana-Apalai) to 90.7% (Awa-Guaja) with a mean prevalence of 50.2%. Seroreactivity was detected to C. pneumoniae and to all serotypes of C. trachomatis tested; furthermore, we report clear evidence of the as-yet-undescribed occurrence of serotype A of C. trachomatis. CONCLUSIONS: Specific seroreactivity not only accounts for the large extent of dissemination of C. trachomatis in the Amazon region of Brazil but also shows an expanded area of occurrence of serotype A outside the epidemiological settings previously described. Furthermore, these data suggest possible routes of Chlamydia introduction into the Amazon region from the massive human migration that occurred during the 1,700s.

Report of new cases of Trypanosoma caninum in Brazil

INTRODUCTION: Trypanosoma caninum is a protozoan species recently described in dogs, whose occurrence has been reported in areas of overlap with visceral leishmaniasis. METHODS: Trypanosoma sp. were isolated from nine dogs and characterized by molecular methods. RESULTS: PCR and sequencing confirmed the presence of T. caninum in all dogs, revealing two new areas of transmission: Barra Mansa and São João do Piauí. CONCLUSIONS: The nine new cases described, when added to those already published, account for 62 cases of natural infection by T. caninum and show the geographical spread of this species to new areas, where other trypanosomatids circulate.

Cryptococcosis in Atlántico, Colombia: an approximation of the prevalence of this mycosis and the distribution of the etiological agent in the environment

ABSTRACTINTRODUCTION:Cryptococcosis is an invasive disease acquired by inhalation of infectious propagules from the environment. Currently, compulsory notification of the spread of this disease is not required in Colombia. However, reporting of human immunodeficiency virus (HIV)/acquired immune deficiency syndrome cases to the National Surveillance System has suggested that there is a growing population at risk of contracting cryptococcosis. Few studies have described the occurrence of cryptococcosis in Colombia. Therefore, in this study, we examined the pathology of this disease in Atlántico, Colombia and determined the distributions of Cryptococcus neoformans and Cryptococcus gattii in the environment.METHODS:Clinical samples/isolates were gathered from cases of cryptococcosis previously diagnosed at health institutions in Atlántico, and surveys were completed by clinicians. The environmental study considered 32 sampling points and three tree species, i.e., Quickstick ( Gliricidia sepium ), Almond ( Terminalia catappa ), and Pink trumpet ( Tabebuia rosea ). Environmental and clinical samples/isolates were analyzed for phenotypic and genotypic confirmation.RESULTS:From 1997-2014, 41 cases of cryptococcosis were reported. The mean patient age was 40.5 years (range: 18-63 years); 76% were men, and 78% were HIV positive. Isolation was possible in 38 cases ( C. neoformans , molecular type VNI in 37 cases and C. gattii , molecular type VGI in one case). In 2012-2014, 2,068 environmental samples were analyzed with a positivity of 0.4% ( C. neoformans , molecular type VNI) in Almond and Pink trumpet trees.CONCLUSIONS:Cryptococcus neoformans , molecular type VNI had a higher prevalence than C. gattii and was associated with human exposure and the pathogenesis of cryptococcosis in this geographical region.

Critical analysis of old and new vaccines against N. meningitidis serogroup C, considering the meningococcal disease epidemiology in Brazil

Worldwide, the impact of meningococcal disease is substantial, and the potential for the introduction and spread of more virulent strains of N. meningitidis or strains with increased resistance to current antibiotics causes concern, making prevention essential. OBJECTIVES: Review the indications for meningococcal disease vaccines, considering the epidemiological status in Brazil. METHODS: A critical literature review on this issue using the Medline and Lilacs databases. RESULTS: In Brazil, MenB and MenC were the most important serogroups identified in the 1990s. Polysaccharide vaccines available against those serogroups can offer only limited protection for infants, the group at highest risk for meningococcal disease. Additionally, polysaccharide vaccines may induce a hypo-responsive state to MenC. New meningococcal C conjugate vaccines could partially solve these problems, but it is unlikely that in the next few years a vaccine against MenB that can promote good protection against multiple strains of MenB responsible for endemic and epidemic diseases will become available. CONCLUSIONS: In order to make the best decision about recommendations on immunization practices, better quality surveillance data are required. In Brazil, MenC was responsible for about 2,000 cases per year during the last 10 years. New conjugate vaccines against MenC are very effective and immunogenic, and they should be recommended, especially for children less than 5 years old. Polysaccharide vaccines should be indicated only in epidemic situations and for high-risk groups. Until new vaccines against MenC and MenB are available for routine immunization programs, the most important measure for controlling meningococcal disease is early diagnosis of these infections in order to treat patients and to offer chemoprophylaxis to contacts.

Comparative studies on the growth and reproductive performances of Rhodnius prolixus reared on different blood sources

Host blood source was found to affect both the development and the reproductive performance of Rhodnius prolixus. The insects were reared on citrated human, rabbit, chicken, sheep and horse blood sources, through a membrane feeder, during an entire life cycle, from eggs to adults. Development and reproduction in terms of the number of unfed insects, number of moulting, mortality intermoulting period, number of egg/female, conversion of blood into egg (mg meal/egg) and percentage of hatch as effective physiological parameters were investigated. Our results showed that human or rabbit blood meals were more nutritionally efficient than the other blood samples used because (i) the insects developed faster, presented low mortality and about 80% of them reached the adult stage; and (ii) females oviposited an average of at least 100% more eggs. The inefficiency of chicken and horse blood sources as diets for R. prolixus was manifested in (i) a decrease of the amount of ingested blood and (ii) only a reasonable nutritional quality. The inadequacy of sheep blood was observed by a mortality extremely high, poor moulting response and drastic reduction in egg production.

The feasibility of forecasting influenza epidemics in Cuba

A large influenza epidemic took place in Havana during the winter of 1988. The epidemiologic surveillance unit of the Pedro Kouri Institute of Tropical Medicine detected the begining of the epidemic wave. The Rvachev-Baroyan mathematical model of the geographic spread of an epidemic was used to forecast this epidemic under routine conditions of the public health system. The expected number of individuals who would attend outpatient services, because of influenza-like illness, was calculated and communicated to the health authorities within enough time to permit the introduction of available control measures. The approximate date of the epidemic peak, the daily expected number of individuals attending medical services, and the approximate time of the end of the epidemic wave were estimated. The prediction error was 12%. The model was sufficienty accurate to warrant its use as a pratical forecasting tool in the Cuban public health system.

Basic biochemical investigations as rationale for the design of original antimalarial drugs. An example of phospholipid metabolism

The future of antimalarial chemotherapy is particulary alarming in view of the spread of parasite cross-resistances to drugs that are not even structurally related. Only the availability of new pharmacological models will make it possible to select molecules with novel mechanisms of action, thus delaving resistance and allowing the development of new chemotherapeutic strategies. We reached this objective in mice. Our approach is hunged on fundamental and applied research begun in 1980 to investigate to phospholipid (PL) metabolism of intraerythrocytic Plasmodium. This metabolism is abundant, specific and indispensable for the production of Plasmodium membranes. Any drug to interfere with this metabolism blocks parasitic development. The most effective interference yet found involves blockage of the choline transporter, which supplies Plasmodium with choline for the synthesis of phosphatidylcholine, its major PL, this is a limiting step in the pathway. The drug sensitivity thereshold is much lower for the parasite, which is more dependent on this metabolism than host cells. The compounds show in vitro activity against P. falciparum at 1 to 10 nM. They show a very low toxicity against a lymphblastoid cell line, demonstrating a total abscence of correlation between growth inhibition of parasites and lymphoblastoid cells. They show antimalarial activity in vivo, in the P. berghei or P. chabaudi/mouse system, at doses 20-to 100-fold lower than their in acute toxicity limit. The bioavailability of a radiolabeled form of the product seemed to be advantageous (slow blood clearance and no significant concentration in tissues). Lastly, the compounds are inexpensive to produce. They are stable and water-soluble.

Molecular Epidemiologic Typing Systems of Bacterial Pathogens: Current Issues and Perpectives

The epidemiologic typing of bacterial pathogens can be applied to answer a number of different questions: in case of outbreak, what is the extent and mode of transmission of epidemic clone(s )? In case of long-term surveillance, what is the prevalence over time and the geographic spread of epidemic and endemic clones in the population? A number of molecular typing methods can be used to classify bacteria based on genomic diversity into groups of closely-related isolates (presumed to arise from a common ancestor in the same chain of transmission) and divergent, epidemiologically-unrelated isolates (arising from independent sources of infection). Ribotyping, IS-RFLP fingerprinting, macrorestriction analysis of chromosomal DNA and PCR-fingerprinting using arbitrary sequence or repeat element primers are useful methods for outbreak investigations and regional surveillance. Library typing systems based on multilocus sequence-based analysis and strain-specific probe hybridization schemes are in development for the international surveillance of major pathogens like Mycobacterium tuberculosis. Accurate epidemiological interpretation of data obtained with molecular typing systems still requires additional research on the evolution rate of polymorphic loci in bacterial pathogens.

Development of Rhodnius prolixus (Hemiptera: Reduviidae) under Constant and Cyclic Conditions of Temperature and Humidity

Development of Rhodnius prolixus after eclosion until the adult stage was studied at constant temperatures (T), 15, 20, 25, 28, 35°C, and relative humidities (RH), 75, 86 and 97%, and fluctuating (16/8 hr) temperatures, T I/II, 15/28°C, 20/25°C, 25/28°C and 25/35°C, and relative humidities, RH I/II, 86/75% and 97/75%. Eclosion or molting were not observed at 15°C and 86 or 97% RH, respectively. At 35°C and 75% RH only few insects molted. By alternating T I/II, 15/28°C and 25/35°C, insects developed at high frequency. Cumulating the average lengths of the interphases within independent groups for each instar, R. prolixus reached the adult stage most rapidly (86.7 days) and at highest frequency per instar (mean: 91.8%) at 28°C and 75% RH. Under fluctuating T I/II, development was completed within 100 days or less at 25/28°C and 25/35°C with high rates of hatch and molting. Development was slowest at fluctuating TI/II, 15/28°C and 20/25°C (>185 days), and at constant 20°C (>300 days). Mortality was higher at constant 97% RH or fluctuating RH I, 97%, than at constant or fluctuating 86% RH. Refeeding was minimal at optimal conditions of T and RH for development. The most refeeding was observed at a constant 35°C.

Genetic variability among populations of Lutzomyia (Psathyromyia) shannoni (Dyar 1929) (Diptera: Psychodidae: Phlebotominae) in Colombia

Polyacrylamide gel electrophoresis was used to elucidate genetic variation at 13 isozyme loci among forest populations of Lutzomyia shannoni from three widely separated locations in Colombia: Palambí (Nariño Department), Cimitarra (Santander Department) and Chinácota (Norte de Santander Department). These samples were compared with a laboratory colony originating from the Magdalena Valley in Central Colombia. The mean heterozygosity ranged from 16 to 22%, with 2.1 to 2.6 alleles detected per locus. Nei's genetic distances among populations were low, ranging from 0.011 to 0.049. The estimated number of migrants (Nm=3.8) based on Wright's F-Statistic, F ST, indicated low levels of gene flow among Lu. shannoni forest populations. This low level of migration indicates that the spread of stomatitis virus occurs via infected host, not by infected insect. In the colony sample of 79 individuals, the Gpi locus was homozygotic (0.62/0.62) in all females and heterozygotic (0.62/0.72) in all males. Although this phenomenon is probably a consequence of colonization, it indicates that Gpi is linked to a sex determining locus.

Effects of chloroquine and sulfadoxine/pyrimethamine on gametocytes in patients with uncomplicated Plasmodium falciparum malaria in Colombia

The effect of antimalarials on gametocytes can influence transmission and the spread of drug resistance. In order to further understand this relationship, we determined the proportion of gametocyte carriers over time post-treatment in patients with uncomplicated Plasmodium falciparum malaria who were treated with either chloroquine (CQ) or sulfadoxine/pyrimethamine (SP). The overall proportion of gametocyte carriers was high (85%) and not statistically significantly different between the CQ and SP treatment groups. However, an increased risk of carrying gametocytes on day 14 of follow up (1.26 95% CI 1.10-1.45) was found among patients having therapeutic failure to CQ compared with patients having an adequate therapeutic response. This finding confirms and extends reports of increased risk of gametocytaemia among CQ resistant P. falciparum.

Risk of hepatitis C among brazilian ex-soccer players

In order to evaluate the significance of injecting vitamins complexes and stimulants minutes before soccer games and its role in spread of hepatitis C virus (HCV) we interviewed and tested 40 ex-soccer players, who played professionally in Mato Grosso, Brazil, between 1970 and 1989. Five players were found anti-HCV positive with enzyme-immunoassay. When re-tested by imunoblot (RIBA), three of these five were confirmed to be positive reacting. The anti-HCV positivity (7.5%) was higher than usually found among blood donors (0.9%) in this region (p < 0.01). None of the players had had prior history of any risk factor that might indicate HCV exposure. We suggest that the common practice of soccer players in the inner part of Brazil in the 70's and 80's, to receive fortifying injections, often with shared syringes, may place ex-soccer players in a potencial risk group for HCV infection and warrants further investigation and attention by public health workers.

The origin and dispersion of human parasitic diseases in the Old World (Africa, Europe and Madagascar)

The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani - the dog - has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar). Migrants coming from Africa and Arabia brought with them the two African forms of bilharziosis: S. haematobium and S. mansoni.

Effects of antifolates - co-trimoxazole and pyrimethamine-sulfadoxine - on gametocytes in children with acute, symptomatic, uncomplicated, Plasmodium falciparum malaria

Antimalarial drugs including the antifolate, pyrimethamine-sulfadoxine (PS), can modulate the prevalence and intensities of gametocytaemia following treatment of acute malaria infections. They may also directly influence the transmission and spread of drug insensitivity. Little is known of the effects of co-trimoxazole (Co-T), another antifolate antimalarial, on gametocytes in children with acute malaria infections. We compared the effects of Co-T and PS on the prevalence and intensities of gametocytaemia and gametocyte sex ratios in 102 children aged 0.5-12 years presenting with acute and uncomplicated falciparum malaria. Compared to pre-treatment, both drugs significantly increased gametocyte carriage post-initiation of treatment. However, gametocyte carriage was significantly lower on day 14 in those treated with Co-T than PS. Significant increase in gametocytaemia with time occurred in PS - but not Co-T-treated children. Kaplan-Meier survival curve of the cumulative probability of remaining gametocyte-free in children who were agametocytaemic at enrolment showed that by day 7 of follow up, children treated with PS had a significantly higher propensity to have developed gametocytes than in Co-T-treated children (Log-rank statistic 5.35, df = 1, P = 0.02). Gametocyte sex ratio changes were similar following treatment with both drugs. PS and Co-T treatment of acute malaria infections in children from this endemic area is associated with significant increases in prevalence and intensities of gametocytaemia but these effects are more marked in those treated with PS than Co-T.

A genotyping study of human immunodeficiency virus type-1 drug resistance in a small Brazilian municipality

In Brazil, surveillance studies on antiretroviral drug resistance among drug-naïve and treatment-experienced patients have focused primarily on patients living in large urban centers. As the epidemic spreads towards small municipalities and the innermost parts of the country, it will be essential to monitor the prevalence of antiretroviral drug resistance in these areas. We report the first survey on the prevalence of antiretroviral drug resistance in a small Brazilian municipality. Between July 1999 and March 2005, 72 adult human immunodeficiency virus type-1(HIV-1)-infected patients received care at the Municipal HIV/AIDS Program of the small, southeastern municipality of Miracema, state of Rio de Janeiro. A genotyping study of antiretroviral drug resistance was performed in 54 patients. Among 27 samples from treatment-experienced patients, 9 (33.3%) harbored strains with reduced drug susceptibility. Among these, 6 had reduced susceptibility to reverse transcriptase (RT) inhibitors and 3 to both RT and protease inhibitors. No primary antiretroviral drug resistance was recorded among 27 drug-naïve subjects. The relatively low prevalence of resistance mutations in the Miracema cohort argues against the concern that resource-poor settings should not implement widespread accessibility to standard of care antiretroviral combinations due to the possibility of sub-optimal adherence leading to the emergence and spread of drug-resistant strains.