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Background: Leprosy transmission is ongoing; globally and within Bangladesh. Household contacts of leprosy cases are at increased risk of leprosy development. Identification of household contacts at highest risk would optimize this process. Methods: The temporal pattern of new case presentation amongst household contacts was documented in the COCOA (Contact Cohort Analysis) study. The COCOA study actively examined household contacts of confirmed leprosy index cases identified in 1995, and 2000–2014, to provide evidence for timings of contact examination policies. Data was available on 9527 index cases and 38303 household contacts. 666 household contacts were diagnosed with leprosy throughout the follow-up (maximum follow-up of 21 years). Risk factors for leprosy development within the data analysed, were identified using Cox proportional hazard regression. Findings: The dominant risk factor for household contacts developing leprosy was having a highly skin smear positive index case in the household. As the grading of initial slit skin smear of the index case increased from negative to high positive (4–6), the hazard of their associated household contacts developing leprosy increases by 3.14 times (p<0.001). Being a blood relative was not a risk factor, no gender differences in susceptibility were found. Interpretation: We found a dominance of a single variable predicting risk for leprosy transmission–skin smear positive index cases. A small number of cases are maintaining transmission in the household setting. Focus should be performing contact examinations on these households and detecting new skin smear positive index cases. Conducting slit-skin smears on new cases is needed for predicting risk; such services need supporting. If skin smear positive cases are sustaining leprosy infection within the household setting, the administration of single-dose rifampicin (SDR) to household contacts as the sole intervention in Bangladesh will not be effective. Author summary: The number of newly detected leprosy cases worldwide has remained stable over the last ten years. Household contacts of leprosy cases are at increased risk of leprosy development. Household contact examinations and case detection are critical aspects of control. Specific risk factors (recognizable by field staff) for leprosy development need to be identified to aid these control efforts. Targeted household examinations could increase early case detection: this is important because untreated leprosy cases are sustaining transmission. This is the largest, most comprehensive study of development of leprosy in household contacts conducted recently with a maximum follow-up of 21 years. We found a single dominant risk factor for the development of leprosy in the household setting, namely slit skin smear positivity in the index case. This is important for leprosy control because household contact examinations can be focused on contacts at highest risk. Implementation would be simple as the risk factor is identified by leprosy staff in the field. Prioritising households known to be at highest risk of leprosy development would allow efficient allocation of resources. Our results cast doubt on the success of administering the recommended prophylactic intervention for contacts; the use of this intervention needs to be re-evaluated. [ABSTRACT FROM AUTHOR]

Background: Food shortage was associated with leprosy in two recent studies investigating the relation between socioeconomic factors and leprosy. Inadequate intake of nutrients due to food shortage may affect the immune system and influence the progression of infection to clinical leprosy. We aimed to identify possible differences in dietary intake between recently diagnosed leprosy patients and control subjects. Methods: In a leprosy endemic area of Bangladesh, newly diagnosed leprosy patients and control subjects were interviewed about their socioeconomic situation, health and diet. Dietary intakes were recorded with a 24-hour recall, from which a Dietary Diversity Score (DDS) was calculated. Body Mass Index (BMI) was calculated and Household Food Insecurity Access Scale (HFIAS) was filled out for every participant. Using logistic regression, a univariate, block wise multivariate, and an integrated analysis were carried out. Results: 52 leprosy cases and 100 control subjects were included. Food shortage was more common, dietary diversity was lower and household food insecurity was higher in the patient group. Patients consumed significantly less items from the DDS food groups 'Meat and fish' and 'Other fruits and vegetables.' Lower food expenditure per capita, lower BMI, lower DDS and absence of household food stocks are the main factors associated with an increased risk of having leprosy. Conclusion: Low income families have only little money to spend on food and consequently have a low intake of highly nutritious non-rice foods such as meat, fish, milk, eggs, fruits and vegetables. Development of clinical leprosy could be explained by deficiencies of the nutrients that these foods normally provide. Author Summary: Even though leprosy is one of the oldest diseases known to mankind, there is still a lot unknown about its transmission and why some people develop the disease and others do not. Leprosy is often seen as a disease of the poor, but which aspects of poverty are associated with leprosy are still under study. Recently though, food shortage has been identified as a risk factor for leprosy in two socioeconomic studies. In our study, lead in a poor area of Bangladesh, we further investigated this link by interviewing recently diagnosed leprosy patients during a food shortage period. We found that compared to a control population, leprosy patients have less money to spend on food, have less household food stocks and have a less diverse diet. The patient group had a lower consumption of highly nutritious foods such as meat, fish, eggs, milk, fruits and vegetables. An inadequate diet for a longer period of time leads to nutrient deficiencies. The body's immune system, however, needs proteins, vitamins and minerals to effectively fight off infections. We conclude that people who are living in poverty and who are not able to get an adequate, diverse diet have a higher chance of developing leprosy. [ABSTRACT FROM AUTHOR]

Background: Leprosy is remaining prevalent in the poorest areas of the world. Intensive control programmes with multidrug therapy (MDT) reduced the number of registered cases in these areas, but transmission of Mycobacterium leprae continues in most endemic countries. Socio-economic circumstances are considered to be a major determinant, but uncertainty exists regarding the association between leprosy and poverty. We assessed the association between different socio-economic factors and the risk of acquiring clinical signs of leprosy. Methods and Findings: We performed a case-control study in two leprosy endemic districts in northwest Bangladesh. Using interviews with structured questionnaires we compared the socio-economic circumstances of recently diagnosed leprosy patients with a control population from a random cluster sample in the same area. Logistic regression was used to compare cases and controls for their wealth score as calculated with an asset index and other socio-economic factors. The study included 90 patients and 199 controls. A recent period of food shortage and not poverty per se was identified as the only socio-economic factor significantly associated with clinical manifestation of leprosy disease (OR 1.79 (1.06–3.02); p = 0.030). A decreasing trend in leprosy prevalence with an increasing socio-economic status as measured with an asset index is apparent, but not statistically significant (test for a trend: OR 0.85 (0.71–1.02); p = 0.083). Conclusions: Recent food shortage is an important poverty related predictor for the clinical manifestation of leprosy disease. Food shortage is seasonal and poverty related in northwest Bangladesh. Targeted nutritional support for high risk groups should be included in leprosy control programmes in endemic areas to reduce risk of disease. Author Summary: Although intensive control programs reduced the prevalence of leprosy worldwide, new cases of this infectious disease are still detected in several of the poorest areas of the world. Therefore the disease is known as a disease of poverty. To be able to control the disease it is important to know which aspects of poverty play a role in transmission and acquiring clinical signs of disease. In this study socio-economic circumstances of recently diagnosed leprosy patients were compared with those of a control population in the poverty stricken northwest area of Bangladesh where leprosy is common. A recent period of food shortage was the only socio-economic factor that was found related to leprosy disease in this study and not poverty as such. Food shortage is seasonal and poverty related in northwest Bangladesh, while malnutrition is known to lower immunity and make people more vulnerable to infectious diseases. Therefore it was concluded that malnutrition as an aspect of poverty played an important role in the development of the clinical signs of leprosy. We therefore recommend that nutritional support for high risk groups should be included in leprosy control programmes to reduce risk of disease in areas where leprosy is common. [ABSTRACT FROM AUTHOR]

Background: Leprosy is remaining prevalent in the poorest areas of the world. Intensive control programmes with multidrug therapy (MDT) reduced the number of registered cases in these areas, but transmission of Mycobacterium leprae continues in most endemic countries. Socio-economic circumstances are considered to be a major determinant, but uncertainty exists regarding the association between leprosy and poverty. We assessed the association between different socio-economic factors and the risk of acquiring clinical signs of leprosy. Methods and Findings: We performed a case-control study in two leprosy endemic districts in northwest Bangladesh. Using interviews with structured questionnaires we compared the socio-economic circumstances of recently diagnosed leprosy patients with a control population from a random cluster sample in the same area. Logistic regression was used to compare cases and controls for their wealth score as calculated with an asset index and other socio-economic factors. The study included 90 patients and 199 controls. A recent period of food shortage and not poverty per se was identified as the only socio-economic factor significantly associated with clinical manifestation of leprosy disease (OR 1.79 (1.06-3.02); p = 0.030). A decreasing trend in leprosy prevalence with an increasing socio-economic status as measured with an asset index is apparent, but not statistically significant (test for a trend: OR 0.85 (0.71-1.02); p = 0.083). Conclusions: Recent food shortage is an important poverty related predictor for the clinical manifestation of leprosy disease. Food shortage is seasonal and poverty related in northwest Bangladesh. Targeted nutritional support for high risk groups should be included in leprosy control programmes in endemic areas to reduce risk of disease. [ABSTRACT FROM AUTHOR]

Background: With 249,007 new leprosy patients detected globally in 2008, it remains necessary to develop new and effective interventions to interrupt the transmission of M. leprae. We assessed the economic benefits of single dose rifampicin (SDR) for contacts as chemoprophylactic intervention in the control of leprosy. Methods: We conducted a single centre, double blind, cluster randomised, placebo controlled trial in northwest Bangladesh between 2002 and 2007, including 21,711 close contacts of 1,037 patients with newly diagnosed leprosy. We gave a single dose of rifampicin or placebo to close contacts, with follow-up for four years. The main outcome measure was the development of clinical leprosy. We assessed the cost effectiveness by calculating the incremental cost effectiveness ratio (ICER) between the standard multidrug therapy (MDT) program with the additional chemoprophylaxis intervention versus the standard MDT program only. The ICER was expressed in US dollars per prevented leprosy case. Findings: Chemoprophylaxis with SDR for preventing leprosy among contacts of leprosy patients is cost-effective at all contact levels and thereby a cost-effective prevention strategy. In total, $6,009 incremental cost was invested and 38 incremental leprosy cases were prevented, resulting in an ICER of $158 per one additional prevented leprosy case. It was the most cost-effective in neighbours of neighbours and social contacts (ICER $214), slightly less cost-effective in next door neighbours (ICER $497) and least cost-effective among household contacts (ICER $856). Conclusion: Chemoprophylaxis with single dose rifampicin given to contacts of newly diagnosed leprosy patients is a cost-effective intervention strategy. Implementation studies are necessary to establish whether this intervention is acceptable and feasible in other leprosy endemic areas of the world. Author Summary: In 2008, 249,007 new leprosy patients were detected in the world. It therefore remains necessary to develop new and effective interventions to interrupt the transmission of M. leprae. We assessed the economic benefits of single dose rifampicin (SDR) for contacts as chemoprophylactic intervention in the control of leprosy. The study is based on a large trial including 21,711 contacts of 1,037 patients with newly diagnosed leprosy. We gave a single dose of rifampicin or placebo to contacts and followed them up for four years. The main outcome measure was the development of clinical leprosy. The cost effectiveness was expressed in US dollars per prevented leprosy case. Chemoprophylaxis with SDR for preventing leprosy among contacts of leprosy patients is cost-effective at all contact levels and thereby a cost-effective prevention strategy. In total $6,009 was invested and 38 leprosy cases were prevented after 2 years, costing $158 per prevented leprosy case. Implementation studies are necessary to establish whether this intervention is acceptable and feasible in other leprosy endemic areas of the world. [ABSTRACT FROM AUTHOR]