A Qualitative Exploration of Social Contact Patterns Relevant to Airborne Infectious Diseases in Northwest Bangladesh.

In South Asia, the burden of infectious diseases is high. Socioeconomically and culturally-defined social interaction patterns are considered to be an important determinant in the spread of diseases that are transmitted through person-to-person contact. Understanding of the contact patterns in this region can be helpful to develop more effective control measures. Focus group discussions were used in exploring social contact patterns in northwest Bangladesh. The patterns were assessed for perceived relevance to the spread of airborne infectious diseases, with special focus on diseases, like leprosy and tuberculosis, in which the role of social determinants is well-recognized. Highly-relevant social contact patterns inside the home and the neighbourhood, across age and sex groups, were reported in all group discussions. Outside the home, women and girls reported relevant contacts limited to the close neighbourhood while men mentioned high relevant contacts beyond. This implies that, in theory, infectious diseases can easily be transmitted across age and sex groups in and around the home. Adult men might play a role in the transmission of airborne infectious diseases from outside this confined area since only this group reported highly-relevant social contacts beyond the home. This concept needs further exploration but control programmes in the South Asian region could benefit from considering differences in social contact patterns by gender for risk assessments and planning of preventive interventions.

Comparison of two rapid tests for anti-phenolic glycolipid-I serology in Brazil and Nepal

The diagnosis of leprosy continues to be based on clinical symptoms and early diagnosis and treatment are critical to preventing disability and transmission. Sensitive and specific laboratory tests are not available for diagnosing leprosy. Despite the limited applicability of anti-phenolic glycolipid-I (PGL-I) serology for diagnosis, it has been suggested as an additional tool to classify leprosy patients (LPs) for treatment purposes. Two formats of rapid tests to detect anti-PGL-I antibodies [ML immunochromatography assay (ICA) and ML Flow] were compared in different groups, multibacillary patients, paucibacillary patients, household contacts and healthy controls in Brazil and Nepal. High ML Flow intra-test concordance was observed and low to moderate agreement between the results of ML ICA and ML Flow tests on the serum of LPs was observed. LPs were "seroclassified" according to the results of these tests and the seroclassification was compared to other currently used classification systems: the World Health Organization operational classification, the bacilloscopic index and the Ridley-Jopling classification. When analysing the usefulness of these tests in the operational classification of PB and MB leprosy for treatment and follow-up purposes, the ML Flow test was the best point-of-care test for subjects in Nepal and despite the need for sample dilution, the ML ICA test yielded better performance among Brazilian subjects. Our results identified possible ways to improve the performance of both tests.

A relação entre soroprevalência de anticorpos contra o glicolipídeo fenólico-I entre crianças em idade escolar e endemicidade da hanseníase no Brasil / The relation between seroprevalence of antibodies against phenolic glycolipid-I among school children and leprosy endemicity in Brazil

Os programas de controle da hanseníase se beneficiariam de um método fácil para estimar prevalência e avaliar o impacto das ações de controle na prevalência da doença. A determinação da soroprevalência de anticorpos contra PGL-I através de estudos com crianças em idade escolar foi sugerida como indicador útil da taxa de prevalência da hanseníase a nível municipal.Para investigar se a soropositividade estaria associada aos coeficientes de detecção da hanseníase e se poderia ser usada como indicador da prevalência em outras áreas, 7.073 crianças em três estados endêmicos de hanseníase no Brasil foram testadas. Resultados mostram uma considerável variação da distribuição de soropositividade nas comunidades, independente do número de casos de hanseníase detectados. A soroprevalência foi significativamente menor nos colégios. Nenhuma diferença na distribuição da soropositividade determinada por ELISA ou dipstick foi observada. Nenhuma correlação entre o coeficiente de detecção da hanseníase e soropositividade pôde ser estabelecida.

Leprosy control programs would benefit expressively from an easy method to estimate disease prevalence and to assess the effect of leprosy control measures on disease prevalence. Determination of the seroprevalence of antibodies to PGL-I through school children surveys might be a useful indicator of leprosy prevalence at the district level. To investigate whether seropositivity rates could be related to leprosy detection rates and whether seropositivity could be used as a proximal indicator to predict the leprosy incidence in other areas, 7,073 school children in three different leprosy-endemic states in Brazil were tested. The results show a widely varying distribution of seropositivity in the communities independent of the number of leprosy cases detected. Seroprevalence was significantly lower at private schools. No differences in the patterns of seropositivity between ELISA and dipstick were observed. No correlation between leprosy detection rate and seropositivity rates could be established.

Knowledge and use of preventive measures against malaria in endemic and non-endemic villages in northern Thailand.

The objective of this study was to determine the frequency and determinants of knowledge of malaria in four sites in northern Thailand, and to compare the use of prevention measures between people with and without a knowledge of malaria. An epidemiological survey was conducted in January 2002 among 857 persons living in four sites in northern Thailand. Of the 857 persons, 53% had a knowledge of malaria, ranging from 38% and 51% in non-endemic to 76% and 77% in endemic sites. Headache (89%), shivering (83%) and fever (79%) were the most frequently mentioned symptoms. Younger persons had more knowledge of malaria than older persons; adjusted Odds Ratio (aOR): 3.91 [95% confidence interval (CI): 2.32-6.56] for the 15-29 age group compared to persons 60 years and older. In comparison to men, knowledge of malaria was significantly lower among women (aOR: 2.00, 95%-CI: 1.47-2.70). Persons with knowledge reported a significantly higher use of prevention measures than persons without knowledge of malaria.