Dataset Information

Distinct climate influences on the risk of typhoid compared to invasive non-typhoid Salmonella disease in Blantyre, Malawi.

ABSTRACT: Invasive Salmonella diseases, both typhoid and invasive non-typhoidal Salmonella (iNTS), are seasonal bloodstream infections causing important morbidity and mortality globally in Africa. The reservoirs and transmission of both are not fully understood. We hypothesised that differences in the time-lagged relationships of rainfall or temperature with typhoid and iNTS incidence might infer differences in epidemiology. We assessed the dynamics of invasive Salmonella incidence over a 16-year period of surveillance, quantifying incidence peaks, seasonal variations, and nonlinear effects of rainfall and temperature exposures on the relative risks of typhoid and iNTS, using monthly lags. An increased relative risk of iNTS incidence was short-lasting but immediate after the onset of the rains, whereas that of typhoid was long-lasting but with a two months delayed start, implying a possible difference in transmission. The relative-risk function of temperature for typhoid was bimodal, with higher risk at both lower (with a 1 month lag) and higher (with a ?4 months lag) temperatures, possibly reflecting the known patterns of short and long cycle typhoid transmission. In contrast, the relative-risk of iNTS was only increased at lower temperatures, suggesting distinct transmission mechanisms. Environmental and sanitation control strategies may be different for iNTS compared to typhoid disease.

SUBMITTER: Thindwa D

PROVIDER: S-EPMC6937328 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Distinct climate influences on the risk of typhoid compared to invasive non-typhoid Salmonella disease in Blantyre, Malawi.

Thindwa Deus D Chipeta Michael G MG Henrion Marc Y R MYR Gordon Melita A MA

Scientific reports 20191230 1

Invasive Salmonella diseases, both typhoid and invasive non-typhoidal Salmonella (iNTS), are seasonal bloodstream infections causing important morbidity and mortality globally in Africa. The reservoirs and transmission of both are not fully understood. We hypothesised that differences in the time-lagged relationships of rainfall or temperature with typhoid and iNTS incidence might infer differences in epidemiology. We assessed the dynamics of invasive Salmonella incidence over a 16-year period o ...[more]

PMID: 31889080

Similar Datasets

Project description:BackgroundInvasive Non-typhoidal Salmonella (iNTS) are an important cause of bacteraemia in children and HIV-infected adults in sub-Saharan Africa. Previous research has shown that iNTS strains exhibit a pattern of gene loss that resembles that of host adapted serovars such as Salmonella Typhi and Paratyphi A. Salmonella enterica serovar Bovismorbificans was a common serovar in Malawi between 1997 and 2004.MethodologyWe sequenced the genomes of 14 Malawian bacteraemia and four veterinary isolates from the UK, to identify genomic variations and signs of host adaptation in the Malawian strains.Principal findingsWhole genome phylogeny of invasive and veterinary S. Bovismorbificans isolates showed that the isolates are highly related, belonging to the most common international S. Bovismorbificans Sequence Type, ST142, in contrast to the findings for S. Typhimurium, where a distinct Sequence Type, ST313, is associated with invasive disease in sub-Saharan Africa. Although genome degradation through pseudogene formation was observed in ST142 isolates, there were no clear overlaps with the patterns of gene loss seen in iNTS ST313 isolates previously described from Malawi, and no clear distinction between S. Bovismorbificans isolates from Malawi and the UK. The only defining differences between S. Bovismorbificans bacteraemia and veterinary isolates were prophage-related regions and the carriage of a S. Bovismorbificans virulence plasmid (pVIRBov).ConclusionsiNTS S. Bovismorbificans isolates, unlike iNTS S. Typhiumrium isolates, are only distinguished from those circulating elsewhere by differences in the mobile genome. It is likely that these strains have entered a susceptible population and are able to take advantage of this niche. There are tentative signs of convergent evolution to a more human adapted iNTS variant. Considering its importance in causing disease in this region, S. Bovismorbificans may be at the beginning of this process, providing a reference against which to compare changes that may become fixed in future lineages in sub-Saharan Africa.

Project description:BackgroundDespite advocating for male involvement in antenatal education, there is unmet need for antenatal education information for expectant couples. The objective of this study was to gain a deeper understanding of the education content for couples during antenatal education sessions in Malawi. This is needed for the development of a tailor-made curriculum for couple antenatal education in the country, later to be tested for acceptability, feasibility and effectiveness.MethodsAn exploratory cross sectional descriptive study using a qualitative approach was conducted in semi-urban areas of Blantyre District in Malawi from February to August 2016. We conducted four focus group discussions (FGDs) among men and women independently. We also conducted one focus group discussion with nurses/ midwives, 13 key informant interviews whose participants were drawn from both health-related and non-health related institutions; 10 in-depth interviews with couples and 10 separate in-depth interviews with men who had attended antenatal clinics before with their spouses. All the interviews were audiotaped, transcribed verbatim and translated from Chichewa, the local language, into English. We managed data with NVivo 10.0 and used the thematic content approach as a guide for analysis.ResultsWe identified one overarching theme: couple antenatal education information needs. The theme had three subthemes which were identified based on the three domains of the maternity cycle which are pregnancy, labour and delivery and postpartum period. Preferred topics were; description of pregnancy, care of pregnant women, role of men during perinatal period, family life birth preparedness and complication readiness plan, coitus during pregnancy and after delivery, childbirth and baby care.ConclusionAntenatal education is a potential platform to disseminate information and discuss with male partners the childbearing period and early parenting. Hence, if both men and women were to participate in antenatal education, their information needs should be prioritized. Men and women had similar choices of topics to be taught during couple antenatal education, with some minor variations.Electronic supplementary materialThe online version of this article (10.1186/s12884-018-2137-y) contains supplementary material, which is available to authorized users.

Dataset Information

Distinct climate influences on the risk of typhoid compared to invasive non-typhoid Salmonella disease in Blantyre, Malawi.

Publications

Distinct climate influences on the risk of typhoid compared to invasive non-typhoid Salmonella disease in Blantyre, Malawi.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets