Nonlinear Dynamical Systems for Malaria Transmission and Control: Ross-Macdonald Model

Malaria was declared an emergency in Nigeria and strategies for the control of Malaria in Nigeria were adopted to reduce its prevalence to a level at which the disease will no longer constitute public health problems. In this work, we presented a deterministic (Ross–Macdonald model susceptible, expose/ infected, infectious and recovered) model incorporating the method of control adopted by national Malaria and leprosy control program. We established the disease free and the endemic equilibrium states and carried out the stability analysis of the disease. Free and the equilibrium state. We also carried out numerical simulation of the model to have an insight into the dynamics of the model. We found out that the disease free equilibrium state is stable. The feedback dynamics from mosquito to human and back to mosquito involve considerable time due to the incubation periods of the parasites. In this paper, taking explicit account of the incubation periods of parasites within the human and the mosquito, we first propose a Ross–Macdonald model. The Jacobiant results showed that it would be very difficult to completely eradicate Malaria from Nigeria using the method adopted by national Malaria and leprosy control program.

Low risk of relapse and deformity among leprosy patients who completed multi-drug therapy regimen from 2005 to 2010: A cohort study from four districts in South India

Introduction Relapse of leprosy among patients released from treatment (RFT) is an indicator of the success of anti-leprosy treatment. Due to inadequate follow-up, relapse in leprosy patients after RFT is not systematically documented in India. Relapsed leprosy patients pose a risk in the transmission of leprosy bacilli. We determined the incidence of relapse and deformity among the patients RFT from the leprosy control programme in four districts in South India. Methods We conducted two follow-up surveys in 2012 and 2014 among the leprosy patients RFT between 2005 and 2010. We assessed them for any symptoms or signs of relapse, persistence and deformity. We collected slit skin samples (SSS) for smear examination. We calculated overall incidence of relapse and deformity per 1000 person-years (PY) with 95% confidence intervals (CI) and cumulative risk of relapse. Results Overall, we identified 69 relapse events, 58 and 11, during the first and second follow-up surveys, respectively. The incidence of relapse was 5.42 per 1000 PY, which declined over the years after RFT. The cumulative risk of relapse was 2.24%. The rate of deformity among the relapsed patients was 30.9%. The overall incidence of deformity was 1.65 per 1000 person years. The duration of M. leprae detection in smears ranged between 2.38 and 7.67 years. Conclusions Low relapse and deformity rates in leprosy RFT patients are indicative of treatment effectiveness. However, a higher proportion of detection of deformity among relapsed cases is a cause for concern. Periodic follow-up of RFT patients for up to 3 years to detect relapses early and ensure appropriate treatment will minimize the development of deformity among relapsed patients.

Coinfection of Mycobacterial diseases

Although both mycobacterial infections are endemic in developing countries, the coinfection has hardly been reported in the last decade. The combined National TB & Leprosy Control Programme of Bangladesh came into effect in 1994. Though the Elimination of Leprosy (<1 case / 10,000 population) was achieved nationally in 1998, Bangladesh is still endemic for Tuberculosis. A 10 years cohort study was conducted in six districts of the Northern part of Bangladesh, covered by the Damien Foundation. This cohort consisted of a total of 4,788 leprosy cases registered from 2007 to 2016. Reviewing the records of all these cases, 25 (0.52%) patients were identified as having coinfection with Tuberculosis & Leprosy. All cases were coinfected with smear positive pulmonary TB. This study concludes that duel infection with mycobacteria is uncommon. Early diagnosis is very important for better outcomes of both diseases. CBMJ 2020 July: Vol. 09 No. 02 P: 39-41

Challenges in leprosy control actions in brazilian basic care / Desafios nas ações de controle da hanseníase na atenção básica brasileira

Objetivo: analisar as ações de controle da hanseníase na Atenção Básica no Brasil, a partir da avaliação externa do Programa de Melhoria do Acesso e da Qualidade da Atenção Básica (PMAQ-AB). Método: estudo transversal de abordagem quantitativa realizado a partir de dados secundários coletados junto as equipes de profissionais do PMAQ-AB, 2º ciclo. Resultados: a região Centro-Oeste com maior percentual de equipes com casos registrados de hanseníase(71,20%), sendo a que mais realiza diagnóstico de casos novos(90,2%); grande parte das equipes refere a existência da ficha de notificação(85,9%) e segue acompanhamento do tratamento dos usuários(95,2%); o Sudeste aparece como a região que menos faz busca ativa de faltosos do tratamento(83%); quanto a vigilância intradomiciliar, a maioria dos profissionais entrevistados afirma realizá-la(94,8%). Conclusão: reforça-se a necessidade de melhorias do trabalho das equipes para o atendimento integral às pessoas com hanseníase.

Factors Influencing Leprosy Incidence: A Comprehensive Analysis of Observations in Wenshan of China, Nepal, and Other Global Epidemic Areas

Leprosy remains endemic in some regions and is a global health concern. However, the possible causes and risk factors of the disease remain unclear. Data in Wenshan, China were collected from the Wenshan Institute of Dermatology (1986–2015); data in Nepal were obtained from the Leprosy Control Division, Department of Health Services, Nepal (2011 to 2015); and data from Indonesia, India, and Brazil were collected from WHO records. We assessed the epidemiological trends of leprosy in Wenshan and compared the features of possible causes and risk factors with those of other countries. We then performed a descriptive and statistical analysis to make our study more purposeful and definitive. A total of 3,376 cases were detected in Wenshan from 1986 to 2015. The overall prevalence rate (PR) of leprosy presented a decreasing trend with a peak (4.9/10,000 population) in 1986. The detection of new leprosy cases was higher in males than in females. Visible deformity increased every year since 2005 with a disability of 34.8% in 2015 among new cases. In Nepal, 2,461 leprosy patients received multi-drug therapy (MDT) in 2015 which corresponded to the PR of 0.89/10,000 population. Geographic latitude and socio-economic situations appeared to be the main causes of leprosy, and the healthcare condition was an important factor associated with leprosy incidence. The introduction of MDT effectively reduced leprosy prevalence worldwide. Wenshan (China), Nepal, and other countries share similarities in various aspects with respect to socio-cultural features, geographical distribution, environmental factors, and economic situation, which may contribute to leprosy being endemic in these areas.

Mycobacterium leprae transmission characteristics during the declining stages of leprosy incidence: A systematic review

Background Leprosy is an infectious disease caused by Mycobacterium leprae. As incidence begins to decline, the characteristics of new cases shifts away from those observed in highly endemic areas, revealing potentially important insights into possible ongoing sources of transmission. We aimed to investigate whether transmission is driven mainly by undiagnosed and untreated new leprosy cases in the community, or by incompletely treated or relapsing cases. Methodology/Principal findings A literature search of major electronic databases was conducted in January, 2020 with 134 articles retained out of a total 4318 records identified (PROSPERO ID: CRD42020178923). We presented quantitative data from leprosy case records with supporting evidence describing the decline in incidence across several contexts. BCG vaccination, active case finding, adherence to multidrug therapy and continued surveillance following treatment were the main strategies shared by countries who achieved a substantial reduction in incidence. From 3950 leprosy case records collected across 22 low endemic countries, 48.3% were suspected to be imported, originating from transmission outside of the country. Most cases were multibacillary (64.4%) and regularly confirmed through skin biopsy, with 122 cases of suspected relapse from previous leprosy treatment. Family history was reported in 18.7% of cases, while other suspected sources included travel to high endemic areas and direct contact with armadillos. None of the countries included in the analysis reported a distinct increase in leprosy incidence in recent years. Conclusions/Significance Together with socioeconomic improvement over time, several successful leprosy control programmes have been implemented in recent decades that led to a substantial decline in incidence. Most cases described in these contexts were multibacillary and numerous cases of suspected relapse were reported. Despite these observations, there was no indication that these cases led to a rise in new secondary cases, suggesting that they do not represent a large ongoing source of human-to-human transmission.

Mutation of Gyra Gene Found In Mycobacterium Leprae From Leprosy Patient In West Papua and Papua, Indonesia

Cases of leprosy in Indonesia are still high, especially in the provinces of West Papua, North Maluku and Papua. Drug resistance surveillance and typing strains of Mycobacterium leprae are useful molecular tools for leprosy control especially in the three Provinces. The purpose of this study was to identify mutations in the gyrA M. leprae gene obtained from leprosy patients in the provinces of West Papua and Papua on a molecular basis. M. leprae samples obtained from leprosy patients were extracted and continued with PCR and sequencing in the M. leprae gyrA gene. The sequencing results are aligned with M. leprae TN sequences to identify mutations. The phylogenetic tree was constructed using Mega 7 to get the M. leprae gyrA cluster. The RNAalifold server was employed to generate the conserved 2D structure for the gyrA MSAs. Six variants were found in the gyrA M. leprae obtained from the provinces of West Papua and Papua. The six variants are H71R, K73R, D95G, A101T, R107W, A127V. The existence of mutations in the gyrA M. leprae gene found in this study can be information in the treatment of leprosy in Papua if using Ofloxacin as an alternative treatment. Based on phylogenetic analysis found there are three distinct clusters of gyrA gene. The five variants are H71R, K73R, A101T, R107W, A127V are new variant of gyrA M. leprae. The D95G variant has been confirmed to cause resistance to Fluoroquinolone by in vitro methods, while the H71R, K73R, A101T, R107W, A127V variants are new variants whose effects on the fluoroquinolone are unknown. Thus, further analysis is needed to study the effects of the five variants on ofloxacin.