Possible risk factors for vertical transmission of Chagas' disease

The author emphasizes the importance of the congenital transmission of Chagas' disease and discusses the possible risk factors for transmission such as age, origin, obstetrical history and maternal form of disease. Exacerbation of infection during pregnancy is also considered as a possible risk factor for transmission. Besides, a relationship between the frequency of transmission and gestational age is presented. Concerning breast-feeding, the risk of transmission is directly related to the acute phase of maternal disease and bleeding nipples. The deleterious effects of chagasic infection on the fetus and newborn are also considered.

RISK FACTORS OF HIV-1 VERTICAL TRANSMISSION (VT) AND THE INFLUENCE OF ANTIRETROVIRAL THERAPY (ART) IN PREGNANCY OUTCOME

In the absence of intervention, the rate of vertical transmission of HIV can range from 15-45%. With the inclusion of antiretroviral drugs during pregnancy and the choice of delivery route this amounts to less than 2%. However ARV use during pregnancy has generated several questions regarding the adverse effects of the gestational and neonatal outcome. This study aims to analyze the risk factors for vertical transmission of HIV-1 seropositive pregnant women living in Rio Grande and the influence of the use of ARVs in pregnancy outcome. Among the 262 pregnant women studied the rate of vertical transmission of HIV was found to be 3.8%. Regarding the VT, there was a lower risk of transmission when antiretroviral drugs were used and prenatal care was conducted at the referral service. However, the use of ART did not influence the outcome of pregnancy. However, initiation of prenatal care after the first trimester had an influence on low birth weight, as well as performance of less than six visits increased the risk of prematurity. Therefore, the risk factors analyzed in this study appear to be related to the realization of inadequate pre-natal and maternal behavior.

Chagasic megaesophagus and megacolon diagnosed in childhood and probably caused by vertical transmission

Reports on children presenting symptoms compatible with the chronic phase of Chagas disease are sporadic. We report a case of a 7-year-old boy who had megaesophagus and megacolon, both of them a consequence of the trypanosomiasis. The etiology was established by means of laboratory and histological features. Based on epidemiological data, the authors concluded that vertical transmission was the most probable route of acquisition. This diagnosis should be considered in children presenting similar complaints, even those living away from endemic areas.

A model for intra-familial distribution of an infectious disease (Chagas' disease)

A probabilistic model for intra-familial distribution of infectous disease is proposed and applied to the prevalence of positive serology for Trypanosoma cruzi infection in Northeastern Brazilian sample. This double with one tail excess model fits satisfactorily to the data and its interpretation says that around 51% of these 982 families are free of infection risk; among those that are at risk, 3% have a high risk (0.66), probably due to high domestic infestation of the vector bug; while 97% show a small risk (0.11), probably due to accidental, non-domestic transmission.

Evolutionary Control of Infectious Disease: Prospects for Vectorborne and Waterborne Pathogens

Evolutionary theory may contribute to practical solutions for control of disease by identifying interventions that may cause pathogens to evolve to reduced virulence. Theory predicts, for example, that pathogens transmitted by water or arthropod vectors should evolve to relatively high levels of virulence because such pathogens can gain the evolutionary benefits of relatively high levels of host exploitation while paying little price from host illness. The entrance of Vibrio cholerae into South America in 1991 has generated a natural experiment that allows testing of this idea by determining whether geographic and temporal variations in toxigenicity correspond to variation in the potential for waterborne transmission. Preliminary studies show such correspondences: toxigenicity is negatively associated with access to uncontaminated water in Brazil; and in Chile, where the potential for waterborne transmission is particularly low, toxigenicity of strains declined between 1991 and 1998. In theory vector-proofing of houses should be similarly associated with benignity of vectorborne pathogens, such as the agents of dengue, malaria, and Chagas' disease. These preliminary studies draw attention to the need for definitive prospective experiments to determine whether interventions such as provisioning of uncontaminated water and vector-proofing of houses cause evolutionary reductions in virulence

Failure to demonstrate experimental vertical transmission of the epidemic strain of Chikungunya virus in Aedes albopictus from La Réunion Island, Indian Ocean

Aedes albopictus was responsible for transmission in the first outbreak of chikungunya (CHIK) on La Réunion Island, Indian Ocean, in 2005-2006. The magnitude of the outbreak on this island, which had been free of arboviral diseases for over 30 years, as well as the efficiency of Ae. albopictus as the main vector, raises questions about the maintenance of the CHIK virus (CHIKV) through vertical transmission mechanisms. Few specimens collected from the field as larvae were found to be infected. In this study, Ae. albopictus originating from La Réunion were orally infected with a blood-meal containing 10(8) pfu/mL of the CHIKV epidemic strain (CHIKV 06.21). Eggs from the first and second gonotrophic cycles were collected and raised to the adult stage. The infectious status of the progeny was checked (i) by immunofluorescence on head squashes of individual mosquitoes to detect the presence of viral particles or (ii) by quantitative RT-PCR on mosquito pools to detect viral RNA. We analysed a total of 1,675 specimens from the first gonotrophic cycle and 1,709 from the second gonotrophic cycle without detecting any viral particles or viral RNA. These laboratory results are compared to field records.

VERTICAL TRANSMISSION OF HTLV-I/II: A review

The vertical transmission of the human T-cell lymphotropic virus type I (HTLV-I) occurs predominantly through breast-feeding. Since some bottle-fed children born to carrier mothers still remain seropositive with a frequency that varies from 3.3% to 12.8%, an alternative pathway of vertical transmission must be considered. The prevalence rate of vertical transmission observed in Japan varied from 15% to 25% in different surveys. In Brazil there is no evaluation of this form of transmission until now. However, it is known that in Salvador, Bahia, 0.7% to 0.88% of pregnant women of low socio-economic class are HTLV-I carriers. Furthermore the occurrence of many cases of adult T-cell leukemia/lymphoma and of four cases of infective dermatitis in Salvador, diseases directly linked to the vertical transmission of HTLV-I, indicates the importance of this route of infection among us. Through prenatal screening for HTLV-I and the refraining from breast-feeding a reduction of ~ 80% of vertical transmission has been observed in Japan. We suggest that in Brazil serologic screening for HTLV-I infection must be done for selected groups in the prenatal care: pregnant women from endemic areas, Japanese immigrants or Japanese descendents, intravenous drug users (IDU) or women whose partners are IDU, human immunodeficiency virus carriers, pregnant women with promiscuous sexual behavior and pregnant women that have received blood transfusions in areas where blood donors screening is not performed. There are in the literature few reports demonstrating the vertical transmission of HTLV-II.

No evidence of vertical transmission of HTLV-I in bottle-fed children

The most frequent pathway of vertical transmission of HTLV-I is breast-feeding, however bottle fed children may also become infected in a frequency varying from 4 to 14%. In these children the most probable routes of infection are transplacental or contamination in the birth canal. Forty-one bottle-fed children of HTLV-I seropositive mothers in ages varying from three to 39 months (average age of 11 months) were submitted to nested polymerase chain reaction analysis (pol and tax genes). 81.5% of the children were born by an elective cesarean section. No case of infection was detected. The absence of HTLV-I infection in these cases indicates that transmission by transplacental route may be very infrequent.

VERTICAL TRANSMISSION OF DENGUE VIRUS IN Aedes aegypti COLLECTED IN PUERTO IGUAZÚ, MISIONES, ARGENTINA

A finding of vertical transmission of the DEN 3 virus in male specimens of Aedes aegypti, collected in the 2009 fall-winter period, in Puerto Iguazú city, Misiones, Argentina, using the RT-PCR technique in a 15-specimen pool is reported. This result is analyzed within the context of the epidemiological situation of Argentina's northeast border.

Vertical transmission of Cryptococcus neoformans from a mother coinfected with human immunodeficiency virus: case report

Disseminated infection with Cryptococcus neoformans was observed in a newborn infant who presented fever and respiratory symptoms since the 52nd day of life. The mother was infected by human immunodeficiency virus and presented pulmonary and meningeal cryptococcal infection. This is a rare case of cryptococcal infection with probable maternal-fetal transmission.

Case histories of infectious disease management in developing countries: Phnom Penh and Kabul

Healthcare in developing countries is affected by severe poverty, political instability and diseases that may be of lesser importance in industrialized countries. The aim of this paper was to present two cases and histories of physicians working in hospitals in developing countries and to discuss the opportunities for clinical investigation and collaboration. Cases of patients in Phnom Penh, Cambodia, with histoplasmosis, cryptococcal meningitis, crusted scabies, cerebral lesions and human immunodeficiency virus and of patients in Kabul, Afghanistan, with liver cirrhosis, nephrotic syndrome and facial ulcer are discussed. Greater developmental support is required from industrialized nations, and mutually beneficial cooperation is possible since similar clinical problems exist on both sides (e.g. opportunistic cardiovascular infections). Examples for possible support of hospital medicine include physician interchange visits with defined objectives (e.g. infection control or echocardiography training) and collaboration with clinical investigations and projects developed locally (e.g. epidemiology of cardiovascular diseases or nosocomial bloodborne infections).

Vertical transmission of HIV-1 in the western region of the State of São Paulo

INTRODUCTION: This study aimed to determine the prevalence of vertical HIV-1 transmission in the western region of the State of São Paulo, Brazil. METHODS: The study analyzed the medical records of HIV-1-infected mothers and infant pairs living in the municipalities of São Paulo Regional Health Departments DRS II (Araçatuba) and DRS XI (Presidente Prudente). From March 2001 to March 2006, blood samples were collected and referred to the Molecular Biology Unit of the Adolfo Lutz Institute (ALI), Presidente Prudente. HIV-1-RNA viral load was determined by bDNA assay. RESULTS: The number of births (109/217, 50.2%) and vertical HIV-1 transmissions (6/109, 5.5%) that occurred in DRS II was similar to births (108/217, 49.8%) and vertical transmissions (7/108, 6.5%) in DRS XI (p > 0.05). Although 80% (4/5) of the infected children were male in DRS II, while in DRS XI, 75% (6/8) were female, no differences between sex regarding infected and noninfected children in the regions of Araçatuba and Presidente Prudente were verified. The overall vertical HIV-1 transmission rate was 6%. No consistent reduction in the prevalence of vertical HIV-1 transmission occurred over the years. About 20% of mothers did not know the HIV-1 status of their newborns eight months after delivery. CONCLUSIONS: In the present study, MTCT prevalence rates were about 70% higher than those previously determined in the State of São Paulo, with noreduction throughout the period.Furthermore, a significant number of mothers did not know the HIV-status of their newborns eight months after delivery.

Invasive candidosis: contrasting the perceptions of infectious disease physicians and intensive care physicians

Introduction We analyze how infectious disease physicians perceive and manage invasive candidosis in Brazil, in comparison to intensive care unit specialists. Methods A 38-question survey was administered to 56 participants. Questions involved clinicians' perceptions of the epidemiology, diagnosis, treatment and prophylaxis of invasive candidosis. P < 0.05 was considered statistically significant. Results The perception that candidemia not caused by Candida albicans occurs in less than 10% of patients is more commonly held by intensive care unit specialists (p=0.018). Infectious disease physicians almost always use antifungal drugs in the treatment of patients with candidemia, and antifungal drugs are not as frequently prescribed by intensive care unit specialists (p=0.006). Infectious disease physicians often do not use voriconazole when a patient's antifungal treatment has failed with fluconazole, which also differs from the behavior of intensive care unit specialists (p=0.019). Many intensive care unit specialists use fluconazole to treat candidemia in neutropenic patients previously exposed to fluconazole, in contrast to infectious disease physicians (p=0.024). Infectious disease physicians prefer echinocandins as a first choice in the treatment of unstable neutropenic patients more frequently than intensive care unit specialists (p=0.013). When candidemia is diagnosed, most infectious disease physicians perform fundoscopy (p=0.015), whereas intensive care unit specialists usually perform echocardiograms on all patients (p=0.054). Conclusions This study reveals a need to better educate physicians in Brazil regarding invasive candidosis. The appropriate management of this disease depends on more drug options being available in our country in addition to global coverage in private and public hospitals, thereby improving health care.

Household-based malaria control in a highly endemic area of Africa (Tanzania): determinants of transmission and disease and indicators for monitoring - Kilombero Malaria Project

The Kilombero Malaria Project (KMP) attemps to define opperationally useful indicators of levels of transmission and disease and health system relevant monitoring indicators to evaluate the impact of disease control at the community or health facility level. The KMP is longitudinal community based study (N = 1024) in rural Southern Tanzania, investigating risk factors for malarial morbidity and developing household based malaria control strategies. Biweekly morbidity and bimonthly serological, parasitological and drug consumption surveys are carried out in all study households. Mosquito densities are measured biweekly in 50 sentinel houses by timed light traps. Determinants of transmission and indicators of exposure were not strongly aggregated within households. Subjective morbidity (recalled fever), objective morbidity (elevated body temperature and high parasitaemia) and chloroquine consumption were strongly aggregated within a few households. Nested analysis of anti-NANP40 antibody suggest that only approximately 30% of the titer variance can explained by household clustering and that the largest proportion of antibody titer variability must be explained by non-measured behavioral determinants relating to an individual's level of exposure within a household. Indicators for evaluation and monitoring and outcome measures are described within the context of health service management to describe control measure output in terms of community effectiveness.