Different Mechanisms for Heterogeneity in Leprosy Susceptibility Can Explain Disease Clustering within Households

The epidemiology of leprosy is characterized by heterogeneity in susceptibility and clustering of disease within households. We aim to assess the extent to which different mechanisms for heterogeneity in leprosy susceptibility can explain household clustering as observed in a large study among contacts of leprosy patients

Close contacts with leprosy in newly diagnosed leprosy patients in a high and low endemic area:Comparison between Bangladesh and Thailand

Background: As part of a larger study of the role of close contacts in the transmission of M. leprae, we explored whether the proportion of newly detected cases with a family history of leprosy differs with different incidence rates of leprosy in a population. Methods: Retrospective analysis was performed of contacts of all new leprosy patients diagnosed during a 10-yr period in well-established leprosy control programs in Thailand and Bangladesh. By our definition, a contact group consisted of the new case and of past and present cases who were relatives and in-laws of the new case. For a new case, the nearest index case was defined on the basis of time of onset of symptoms for the cases in the contact group, in combination with the level of closeness of contact between these cases and the new case. Three contact levels were distinguished. In Bangladesh these levels were defined as 'kitchen contact'; 'house contact'; and 'non-house contact'. In Thailand comparable levels were defined as 'house contact'; 'compound contact'; and 'neighbor contact'. Results: In Bangladesh 1333, and in Thailand 129 new patients were included. The average new case detection rate over 10 yrs was 50 per 100,000 general population per year in Bangladesh, and 1.5 per 100,000 in Thailand. In the high endemic area 25% of newly detected cases were known to belong to a contact group and were not the index case of this group, whereas in the low endemic area 62% of newly detected cases had these characteristics. The distribution of the nearest index cases over the three contact levels was comparable in both areas. Just over half of the nearest index cases were found within the immediate family unit ('kitchen' in Bangladesh; 'house' in Thailand). Conclusion: The results indicate that in a low endemic area a higher proportion of newly detected leprosy cases have a family history of leprosy compared to a high endemic area. Different contact levels and their relative risks to contract leprosy need to be established more precisely. In high endemic situations the circle of contacts that should be surveyed may need to be wider than currently practiced.</p

Close contacts with leprosy in newly diagnosed leprosy patients in a high and low endemic area:Comparison between Bangladesh and Thailand

Background: As part of a larger study of the role of close contacts in the transmission of M. leprae, we explored whether the proportion of newly detected cases with a family history of leprosy differs with different incidence rates of leprosy in a population. Methods: Retrospective analysis was performed of contacts of all new leprosy patients diagnosed during a 10-yr period in well-established leprosy control programs in Thailand and Bangladesh. By our definition, a contact group consisted of the new case and of past and present cases who were relatives and in-laws of the new case. For a new case, the nearest index case was defined on the basis of time of onset of symptoms for the cases in the contact group, in combination with the level of closeness of contact between these cases and the new case. Three contact levels were distinguished. In Bangladesh these levels were defined as 'kitchen contact'; 'house contact'; and 'non-house contact'. In Thailand comparable levels were defined as 'house contact'; 'compound contact'; and 'neighbor contact'. Results: In Bangladesh 1333, and in Thailand 129 new patients were included. The average new case detection rate over 10 yrs was 50 per 100,000 general population per year in Bangladesh, and 1.5 per 100,000 in Thailand. In the high endemic area 25% of newly detected cases were known to belong to a contact group and were not the index case of this group, whereas in the low endemic area 62% of newly detected cases had these characteristics. The distribution of the nearest index cases over the three contact levels was comparable in both areas. Just over half of the nearest index cases were found within the immediate family unit ('kitchen' in Bangladesh; 'house' in Thailand). Conclusion: The results indicate that in a low endemic area a higher proportion of newly detected leprosy cases have a family history of leprosy compared to a high endemic area. Different contact levels and their relative risks to contract leprosy need to be established more precisely. In high endemic situations the circle of contacts that should be surveyed may need to be wider than currently practiced.</p

The roles of the general practitioner and sexual health centre in HIV testing:comparative insights and impact on HIV incidence rates in the Rotterdam area, the Netherlands - a cross-sectional population-based study

Background: Access to HIV testing is crucial for detection, linkage to treatment, and prevention. In less urbanised areas, reliance on general practitioners (GPs) for HIV testing is probable, as sexual health centres (SHC) are mostly located within urbanised areas. Limited insight into individuals undergoing HIV testing stems from sparse standard registration of demographics at GPs. This cross-sectional study aims (1) to assess and compare HIV testing at the GP and SHC, and (2) to assess population- and provider-specific HIV incidence. Methods: Individual HIV testing data of GPs and SHC were linked to population register data (aged ≥ 15 years, Rotterdam area, 2015–2019). We reported the proportion HIV tested, and compared GP and SHC testing rates with negative binomial generalised additive models. Data on new HIV diagnoses (2015–2019) from the Dutch HIV Monitoring Foundation relative to the population were used to assess HIV incidence. Results: The overall proportion HIV tested was 1.14% for all residents, ranging from 0.41% for ≥ 40-year-olds to 4.70% for Antilleans. The GP testing rate was generally higher than the SHC testing rate with an overall rate ratio (RR) of 1.61 (95% CI: 1.56–1.65), but not for 15-24-year-olds (RR: 0.81, 95% CI: 0.74–0.88). Large differences in HIV testing rate (1.36 to 39.47 per 1,000 residents) and GP-SHC ratio (RR: 0.23 to 7.24) by geographical area were observed. The GPs’ contribution in HIV testing was greater for GP in areas further away from the SHC. In general, population groups that are relatively often tested are also the groups with most diagnoses and highest incidence (e.g., men who have sex with men, non-western). The overall incidence was 10.55 per 100,000 residents, varying from 3.09 for heterosexual men/women to 24.04 for 25–29-year-olds. Conclusions: GPs have a pivotal role in HIV testing in less urbanised areas further away from the SHC, and among some population groups. A relatively high incidence often follows relatively high testing rates. Opportunities to improve HIV testing have been found for migrants, lower-educated individuals, in areas less urbanised areas and further away from GP/SHC. Strategies include additional targeted testing, via for example SHC branch locations and outreach activities.</p

High Incidence of Pulmonary Tuberculosis a Decade after Immigration, Netherlands

Incidence rates of pulmonary tuberculosis among immigrants from high incidence countries remain high for at least a decade after immigration into the Netherlands. Possible explanations are reactivation of old infections and infection transmitted after immigration. Control policies should be determined on the basis of the as-yet unknown main causes of the persistent high incidence

Population-based screening in a municipality after a primary school outbreak of the SARSCoV-2 Alpha variant, the Netherlands, December 2020–February 2021

An outbreak of SARS-CoV-2 Alpha variant (Pango lineage B.1.1.7) was detected at a primary school (School X) in Lansingerland, the Netherlands, in December 2020. The outbreak was studied retrospectively, and population-based screening was used to assess the extent of virus circulation and decelerate transmission. Cases were SARS-CoV-2 laboratory confirmed and were residents of Lansingerland (November 16(th) 2020 until February 22(th) 2021), or had an epidemiological link with School X or neighbouring schools. The SARS-CoV-2 variant was determined using variant PCR or whole genome sequencing. A questionnaire primarily assessed clinical symptoms. A total of 77 Alpha variant cases were found with an epidemiological link to School X, 16 Alpha variant cases linked to the neighbouring schools, and 146 Alpha variant cases among residents of Lansingerland without a link to the schools. The mean number of self-reported symptoms was not significantly different among Alpha variant infected individuals compared to non-Alpha infected individuals. The secondary attack rate (SAR) among Alpha variant exposed individuals in households was 52% higher compared to non-Alpha variant exposed individuals (p = 0.010), with the mean household age, and mean number of children and adults per household as confounders. Sequence analysis of 60 Alpha variant sequences obtained from cases confirmed virus transmission between School X and neighbouring schools, and showed that multiple introductions of the Alpha variant had already taken place in Lansingerland at the time of the study. The alpha variant caused a large outbreak at both locations of School X, and subsequently spread to neighbouring schools, and households. Population-based screening (together with other public health measures) nearly stopped transmission of the outbreak strain, but did not prevent variant replacement in the Lansingerland municipality

Future prevalence of WHO grade 2 impairment in relation to incidence trends in leprosy: An exploration

Objectives: To explore the relationship between leprosy incidence trends and the future prevalence of World Health Organization (WHO) grade 2 impairment caused by leprosy. Methods: Three scenarios were defined to estimate incidences and prevalences of leprosy impairment beyond 2000, assuming 6%, 12% and 18% annual declines in case detection rate respectively, and 6% impairment among new patients. Case detection data from 1985 to 2000 were used for projecting leprosy incidences up to 2020. To estimate future prevalences of WHO grade 2 impairment, the survival of existing and new impaired individuals was calculated. Results: In the 6% scenario, 410 000 new patients will be detected in 2010 and 250 000 in 2020. The number of people living with WHO grade 2 impairment in these years will be 1.3 and 1.1 million, respectively. The 12% scenario predicts that 210 000 new patients will be detected in 2010 and 70 000 in 2020. The grade 2 prevalences will be 1.2 and 0.9 million, respectively. In the 18% scenario, the incidence will be 110 000 in 2010 and 20 000 in 2020, and the grade 2 prevalences will be 1.1 and 0.8 million, respectively. Conclusions: Declines in numbers of people living with grade 2 impairment lag behind trends in leprosy incidence. The prevalence of people with grade 2 decreases much slower than leprosy incidence and case detection in all three scenarios. This implies that a substantial number of people will live with impairment and will need support, training in self-care and other prevention of disability interventions in the next decades

Testing for sexually transmitted infection: who and where? A data linkage study using population and provider data in the Rotterdam area, the Netherlands.

Background:In the Netherlands, insight into sexually transmitted infection (STI) testing and characteristics of those tested by general practitioners (GPs) and sexual health centres (SHC) is limited. This is partly due to lacking registration of socio-demographics at GPs. We aimed to fill this gap by linking different registers.Methods:Individual STI testing data of GPs and SHC were linked to population register data (aged ≥15 years, Rotterdam area, 2015–2019). We reported population-specific STI positivity, proportion STI tested, and GP-SHC testing rate comparison using negative binomial generalised additive models. Factors associated with STI testing were determined by the provider using logistic regression analyses with generalised estimating equations.Results:The proportion of STI tested was 2.8% for all residents and up to 9.8% for younger and defined migrant groups. STI positivity differed greatly by subgroup and provider (3.0–35.3%). Overall, GPs performed 3 times more STI tests than the SHC. The smallest difference in GP-SHC testing rate was for 20–24-year-olds (SHC key group). Younger age, non-western migratory background, lower household income, living more urbanised, and closer to a testing site were associated with STI testing by either GP or SHC. GPs and SHC partly test different groups: GPs test women and lower-educated more often, the SHC men and middle/higher educated.Conclusions:This study highlights GPs’ important role in STI testing. The GPs’ role in the prevention, diagnosis, and treatment of STIs needs continued support and strengthening. Inter-professional exchange and collaboration between GP and SHC is warranted to reach vulnerable groups

Potential effect of the World Health Organization’s 2011–2015 global leprosy strategy on the prevalence of grade 2 disability: a trend analysis

Objective To assess different countries' chances of attaining the 2011-2015 global leprosy target set by the World Health Organization (WHO) and to assess the strategy's effect on the prevalence of grade 2 disability (G2D). Methods Trends in G2D rate were analysed for Brazil, China, India and Thailand and figures were compared with the WHO target: a 35% decrease by 2015 relative to the 2010 baseline. To estimate the prevalence of G2D in 2015 and 2035 for each country three assumptions were made: (i) maintenance of the current trend; (ii) attainment of the WHO target, and (iii) reduction of G2D by 50% every 5 years relative to 2010. Findings Since 1995, the G2D rate has decreased every 5 years in Brazil, China, India and Thailand by 12.7% (95% confidence interval, CI: 6.6-18.3), 7.7% (95% CI: 1.1-12.8), 53.7% (95% CI: 38.1-65.4) and 35.9% (95% CI: 23.4-46.3), respectively. New cases with G2D detected after 2010 will contribute 15% (Brazil), 3% (China), 2.5% (India) and 4% (Thailand) to the total prevalence of G2D in 2015. If no policies are changed, between 2015 and 2035, the prevalence of G2D will decrease by more than half in China, India and Thailand, and by 16% in Brazil. Conclusion The implications of attaining the WHO target are different for each country and using indicators other than G2D prevalence will help monitor progress. The strategy will not immediately reduce the prevalence of G2D, but if it is applied consistently over the next 25 years, its long-term effect can be substantial