Problems and perspectives for Chagas disease control: in search of a realistic analysis

Chagas disease was an important medical and social problem in almost all of Latin America throughout the twentieth century. It has been combated over a broad swath of this continent over recent decades, with very satisfactory results in terms of vector and transfusional transmission. Today, a surveillance stage still remains to be consolidated, in parallel with appropriate care required for some millions of infected individuals who are today living in endemic and non-endemic areas. Contradictorily, the good results attained have generated excessive optimism and even disregard among health authorities, in relation to this disease and its control. The loss of visibility and priority may be a logical consequence, particularly in Latin American healthcare systems that are still disorganized and overburdened due to insufficiencies of financial and human resources. Consolidation of the victories against Chagas disease is attainable but depends on political will and continual attention from the most consequential protagonists in this struggle, especially the Latin American scientific community.

Tityus stigmurus (Thorell, 1876) (Scorpiones; Buthidae): response to chemical control and understanding of scorpionism among the population

In this study, the events following application of the insecticideDemand 2.5 concentrated solution (CS) in the field, to control Tityus stigmurus, were investigated. Data on attitudes and practices relating to scorpionism were collected using a questionnaire. During the months of May to July 2005, 69 premises were monitored on different days following insecticide treatment, focusing on scorpion frequency and mortality. According to the results, 42% of the premises showed scorpion incidence, with an average of three specimens per house. The highest incidence was recorded during the first week following the treatment. Only 7% of the specimens were found dead. Most (72%) of the population showed knowledge about prevention and control measures. Despite this, 100% of the premises presented breeding sites, mainly in debris (79.7%). These results indicate that the scorpion control method used by health agents during this investigation was not efficient, and the results suggest that the method may have had a dispersive effect on these animals.

Visceral leishmaniasis in Rio de Janeiro, Brazil: eco-epidemiological aspects and control

From 1977 (index case) to 2006, 87 cases of visceral leishmaniasis were confirmed in the municipality of Rio de Janeiro, Brazil, in periurban areas on the continental and coastal slopes of the Pedra Branca massif and the continental slopes of the Gericinó massif. The majority (65.5%) of the patients were more than five years old, predominantly males (61.5%), but without any difference between the sexes below the age of 14 years. The overall fatality rate was 10.4%. Two cases of visceral leishmaniasis/human immunodeficiency virus coinfection were detected. Leishmania chagasi was isolated from human and canine cases. The associations between the presence of phlebotomines and human and canine migrations, disorderly occupation involving degradation of environmental preservation areas and poor socioeconomic conditions may have created a favorable setting for the establishment and propagation of the disease. Close epidemiological surveillance associated with traditional control measures and others (active case researches, land clearing and health education), reduced the incidence of human cases from 2.8 per 100,000 inhabitants in 1981 to less than 0.01 per 100,000 since 1997. The canine infection rates decreased from 4.6% in 1984 to 1.6% in 2008. Lutzomyia longipalpis was not detected in some locations where human and canine cases occurred. In the years 2007 and 2008, no new human cases were reported, but there is a persistent and worrisome residual canine seroprevalence.

Echocardiographic parameters associated with pulmonary congestion in Chagas cardiomyopathy

INTRODUCTION: Discrepancy between the intensity of pulmonary congestion and the grade of cardiomegaly seems to be a common finding of Chagas cardiomyopathy, in spite of significant systolic dysfunction of the left ventricle. Its mechanism has not been established. The aim of this study was to investigate pulmonary congestion and to analyze if it correlated with Doppler echocardiographic parameters in patients with Chagas dilated cardiomyopathy. METHODS: Fifty-five patients with positive serology tests for Trypanosoma cruzi and Chagas dilated cardiomyopathy were studied. Chest x-rays, Doppler echocardiogram and plasmatic brain natriuretic peptide levels were obtained in all patients. The degree of pulmonary venous vessels changes on chest x-ray was graded using a pulmonary congestion score, and then compared to Doppler echocardiographic parameters. RESULTS: Mean age was 48.5 ± 11.2 years and 29% were women. The majority (95%) of patients were in NYHA functional class I and II. Mild pulmonary congestion by chest x-ray was found in 80% of the patients. In a multivariate analysis, left ventricular ejection fraction, right ventricular TEI index and the color M-mode velocity correlated with the degree of pulmonary congestion. CONCLUSIONS: Pulmonary venous changes on chest x-rays are frequent, but usually mild in patients with Chagas dilated cardiomyopathy. The degree of pulmonary congestion correlates with Doppler echocardiographic left and right ventricular dysfunction and with color M-mode velocity.

Is severe visceral leishmaniasis a systemic inflammatory response syndrome? A case control study

INTRODUCTION: The objective of the study is to identify the main risk factors for death by New World visceral leishmaniasis and establish a coherent pathogenic substrate of severe disease based on clinical findings. METHODS: Seventy-six deceased inpatients and 320 successfully treated inpatients with VL were studied in a case control study. RESULTS: Bacterial infection and bleeding were mutually exclusive events leading to death. Five risk factors were unique for death by bacterial infection (malnutrition, pulmonary rales, severe anemia, severe absolute neutropenia and higher neutrophil count), while another six were unique for death by bleeding (jaundice, severe relative neutropenia, severe thrombocytopenia, liver injury, kidney failure, higher bone marrow parasite load). Bacterial infection, bleeding, severe anemia, diarrhea, dyspnea, edema, jaundice and bone marrow parasite load were the main syndromes of visceral leishmaniasis among successfully treated patients. CONCLUSIONS: The data support the idea that bacterial infections are due to immune paralysis. Broad organ and system involvement is plausibly due to the high production of proinflammatory cytokines, whose actions fit well with visceral leishmaniasis. The syndromes and causative mediators are typical of a slowly developing systemic inflammatory response syndrome.

Echocardiographic parameters associated with pulmonary congestion in outpatients with Chagas' cardiomyopathy and non-chagasic cardiomyopathy

INTRODUCTION: Despite significant left ventricular (LV) systolic dysfunction and cardiomegaly, pulmonary congestion does not seem to be a major finding in Chagas' cardiomyopathy (CC). This study sought to identify echocardiographic parameters associated with pulmonary congestion in CC and in dilated cardiomyopathy of other etiologies, such as non-CC (NCC), and to compare pulmonary venous hypertension between the two entities. METHODS: A total of 130 consecutive patients with CC and NCC, with similar echocardiographic characteristics, were assessed using Doppler echocardiography and chest radiography. Pulmonary venous vessel abnormalities were graded using a previously described pulmonary congestion score, and this score was compared with Doppler echocardiographic parameters. RESULTS: NCC patients were older than CC patients (62.4 ± 13.5 × 47.8 ± 11.2, p = 0.00), and there were more male subjects in the CC group (66.2% × 58.5%, p = 0.4). Pulmonary venous hypertension was present in 41 patients in the CC group (63.1%) and in 63 (96.9%) in the NCC group (p = 0.0), the mean lung congestion score being 3.2 ± 2.3 and 5.9 ± 2.6 (p = 0.0), respectively. On linear regression multivariate analysis, the E/e' ratio (β = 0.13; p = 0.0), LV diastolic diameter (β = 0.06; p = 0.06), left atrial diameter (β = 0.51; p = 0.08), and right ventricular (RV) end-diastolic diameter (β = 0.02; p = 0.48) were the variables that correlated with pulmonary congestion in both groups. CONCLUSIONS: Pulmonary congestion was less significant in patients with CC. The degree of LV of systolic and diastolic dysfunction and the RV diameter correlated with pulmonary congestion in both groups. The E/e' ratio was the hallmark of pulmonary congestion in both groups.

Improving tuberculosis control through the partnership between university and the health system

INTRODUCTION: Tuberculosis (TB) control is linked to the availability of qualified methods for microbiological diagnostics; however, microscopy with limited sensitivity is the only method available in many locations. The objective of this study was to evaluate the introduction of culture, drug susceptibility testing (DST), and genotyping in the routine of a Municipal Program of Tuberculosis Control. METHODS: Direct microscopy of sputum and culture in Ogawa-Kudoh were performed on 1,636 samples from 787 patients. DST of positive cultures was performed by resazurin microtiter assay and genotyping by mycobacterial interspersed repetitive units-variable number tandem repeat. RESULTS: A total 91 patients with TB were identified. The culture increased case detection by 32% compared with the microscopy; acquired resistance was 3.3% and the genotyping showed high genetic diversity. CONCLUSIONS: Ogawa-Kudoh contributed significantly to the increase in case detection and is suitable for implementation in poor-resource locations. The acquired resistance rate was lower than that reported in a recent Brazilian survey. The high genetic diversity is possibly related to the high TB prevalence in the population, as well as to early detection and suitable treatment of patients. The interaction between research and health care is important for reorienting the practice, transferring technology, and improving TB control.

Epidemiology of malaria in the municipality of Cruzeiro do Sul, State of Acre, Brazil, in 2010: uses of a control chart at the local level

INTRODUCTION: This study describes the uses of a control chart in the malaria surveillance at the local level, signaling whether there is a need to intensify or adapt control measures. METHODS: The districts of Cruzeiro do Sul (n=14), State of Acre, Brazil, were classified into three groups: I) those with an incidence lower than expected; II) those with an incidence within the expected range; and III) those with an epidemic. RESULTS: Thirteen of the fourteen districts had outbreaks of malaria at some point in 2010, and six districts showed persistent malaria epidemic throughout the year. CONCLUSIONS: The control chart may help the malaria control at the local level.

Primary multidrug-resistant tuberculosis and its control implications in the State of Amazonas, Brazil: report of 3 cases

The occurrence of tuberculosis with first-line multidrug resistance leads to the use of alternative medications, often at higher costs, longer treatment periods, and greater clinical complexity. Here, we report 3 patients with multidrug-resistant tuberculosis. One patient with human immunodeficiency virus died before the sensitivity test was performed. The early diagnosis of multidrug-resistant tuberculosis and appropriate treatment should be priorities of the National Tuberculosis Control Program in order to break the chain of transmission. In addition, the possibility of substituting the proportion method with more modern and faster techniques should be urgently evaluated.

Larval control of Anopheles (Nyssorhinchus) darlingiusing granular formulation of Bacillus sphaericus in abandoned gold-miners excavation pools in the Brazilian Amazon Rainforest

INTRODUCTION: Use of a Bacillus sphaericus based mosquito larvicide was evaluated as an intervention for malaria vector control at a mining site in Amapá, Brazil. Impacts on larval and adult densities of the primary vector Anopheles darlingi were measured over the course of a 52 week study period.METHODS: In Calçoene, State of Amapá, gold mining activity occurs in 19 mining sites in gold-miners of Lourenço. Large pools are formed in mining sites and naturally colonized by Anopheles darlingi. During one year, the impact of applications of VectoLex(r) CG to these larval sources was evaluated. Applications of 20kg/ha were made as needed, based on 10 immature (3rd, 4th instars and pupae) surveillance of health and established thresholds. RESULTS: One hundred percent initial control was observed 48h after each treatment. The pools received from 2-10 (5.3±1.6) treatments during the year. The average re-treatment interval in productive pools was 9.4±4.3 weeks. During weeks 3-52 of the study, mean density of late stage larvae was 78% and pupae were 93% lower in the treated pools than in untreated pools (p< 0.0001, n=51) while reduction of adult mosquitoes was 53% in comparison to the untreated area during the last five months of the study, which were the rainy season (p<0.001).CONCLUSIONS:VectoLex(r) CG reduced immature Anopheles darlingi infestation levels during the entire study period, and reduced adult mosquito populations during the rainy season.

Survey of Bancroftian filariasis infection in humans and Culex mosquitoes in the western Brazilian Amazon region: implications for transmission and control

IntroductionThe aim of this work was to identify possible lymphatic filariasis foci in the western Brazilian Amazonian that could be established from the reports of Rachou in the 1950s. The study was conducted in three cities of the western Brazilian Amazon region - Porto Velho and Guajará-Mirim (State of Rondônia) and Humaitá (State of Amazonas).MethodsFor human infection evaluation thick blood smear stained with Giemsa was used to analyze samples collected from 10pm to 1am. Polymerase chain reaction (PCR) was used to examine mosquito vectors for the presence of Wuchereria bancrofti DNA. Humans were randomly sampled from night schools students and from inhabitants in neighborhoods lacking sanitation. Mosquitoes were collected from residences only.ResultsA total 2,709 night students enrolled in the Program for Education of Young Adults (EJA), and 935 people registered in the residences near the schools were examined, being 641 from Porto Velho, 214 from Guajará-Mirim and 80 from Humaitá. No individual examined was positive for the presence of microfilariae in the blood stream. A total of 7,860 female Culex quinquefasciatus specimens examined were negative by PCR.ConclusionsThis survey including human and mosquito examinations indicates that the western Amazon region of Brazil is not a focus of Bancroftian filariasis infection or transmission. Therefore, there is no need to be included in the Brazilian lymphatic filariasis control program.

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.

Seroprevalence of hantavirus and Yersinia pestis antibodies in professionals from the Plague Control Program

Introduction Professionals who handle rodents in the field and in the laboratory are at risk of infection by the microorganisms harbored by these animals. Methods Serum samples from professionals involved in rodent and Yersinia pestis handling in field or laboratory work were analyzed to determine hantavirus and plague seroprevalence and to establish a relationship between these activities and reports of illnesses. Results Two individuals had antibodies against hantavirus, and two harbored antibodies against the plague; none of the individuals had experienced an illness related to their duties. Conclusions These results confirm the risks of hantavirus- and plague-related field and laboratory activities and the importance of protective measures for such work.