Dataset Information

The changing epidemiology of human African trypanosomiasis among patients from nonendemic countries--1902-2012.

ABSTRACT:

Background

Although human African trypanosomiasis (HAT) is uncommon among patients from non-endemic countries (NEC), there has been an increase in the number of cases reported in recent years.

Methods

A systematic review of the literature was performed. The number of incoming tourists to HAT endemic countries was obtained from the United Nations World Tourism Organization. All HAT cases diagnosed in patients from NEC were included. Immigrants and refugees were excluded. We compared patients during and after the colonial period, and analyzed the relationship between the number of incoming travellers and the number of HAT cases.

Results

Between 1902 and 2012, HAT was reported in 244 patients. Most HAT cases were reported before 1920, and after the year 2000. In the colonial era the average age of patients was lower (32.5±7.8 vs. 43.0±16.1 years, P<0.001), the proportion of females was lower (10.0% vs. 23.9%, P<0.01], most cases were diagnosed in expatriates, missionaries and soldiers (74.3%), and Gambian trypanosomiasis accounted for 86/110, (78%) of cases. In the post-colonial era most patients 91/125 (72.8%) were short-term tourists to game parks in Eastern and South-Eastern Africa (mainly in Tanzania); Rhodesian trypanosomiasis accounted for 94/123 (76.4%) of cases. Between 1995 and 2010 there has been a constant linear increase in the number of incoming tourists to Tanzania, and HAT cases occurred in small outbreaks rather than following a similar linear pattern.

Conclusions

In recent decades HAT patients from NEC are older, and more likely to be tourists who acquired the disease while visiting game-parks in Eastern and South-Eastern Africa. While Rhodesian trypanosomiasis is relatively uncommon among Africans, it now accounts for most cases reported among patients from NEC. Returning febrile travellers without an alternative diagnosis should be evaluated for HAT. Cases among travellers may serve as sentinels for Rhodesian trypanosomiasis "hot spots" in Africa.

SUBMITTER: Neuberger A

PROVIDER: S-EPMC3929605 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The changing epidemiology of human African trypanosomiasis among patients from nonendemic countries--1902-2012.

Neuberger Ami A Meltzer Eyal E Leshem Eyal E Dickstein Yaakov Y Stienlauf Shmuel S Schwartz Eli E

PloS one 20140219 2

<h4>Background</h4>Although human African trypanosomiasis (HAT) is uncommon among patients from non-endemic countries (NEC), there has been an increase in the number of cases reported in recent years.<h4>Methods</h4>A systematic review of the literature was performed. The number of incoming tourists to HAT endemic countries was obtained from the United Nations World Tourism Organization. All HAT cases diagnosed in patients from NEC were included. Immigrants and refugees were excluded. We compare ...[more]

PMID: 24586363

Similar Datasets

Project description:Human African trypanosomiasis (HAT), transmitted by tsetse flies, has historically infected hundreds of thousands of individuals annually in sub-Saharan Africa. Over the last decade, concerted control efforts have reduced reported cases to below 10,000 annually, bringing complete elimination within reach. A potential technology to eliminate HAT involves rendering the flies resistant to trypanosome infection. This approach can be achieved through the introduction of transgenic Sodalis symbiotic bacteria that have been modified to produce a trypanocide, and propagated via Wolbachia symbionts, which confer a reproductive advantage to the paratransgenic tsetse. However, the population dynamics of these symbionts within tsetse flies have not yet been evaluated. Specifically, the key factors that determine the effectiveness of paratransgenesis have yet to be quantified. To identify the impact of these determinants on T.b. gambiense and T.b. rhodesiense transmission, we developed a mathematical model of trypanosome transmission that incorporates tsetse and symbiont population dynamics. We found that fecundity and mortality penalties associated with Wolbachia or recombinant Sodalis colonization, probabilities of vertical transmission, and tsetse migration rates are fundamental to the feasibility of HAT elimination. For example, we determined that HAT elimination could be sustained over 25 years when Wolbachia colonization minimally impacted fecundity or mortality, and when the probability of recombinant Sodalis vertical transmission exceeded 99.9%. We also found that for a narrow range of recombinant Sodalis vertical transmission probability (99.9-90.6% for T.b. gambiense and 99.9-85.8% for T.b. rhodesiense), cumulative HAT incidence was reduced between 30% and 1% for T.b. gambiense and between 21% and 3% for T.b. rhodesiense, although elimination was not predicted. Our findings indicate that fitness and mortality penalties associated with paratransgenic symbionts, as well as tsetse migration rates, are instrumental to HAT elimination, and should be a key focus in the development of paratransgenic symbionts.

Project description:BACKGROUND: Algorithms to diagnose gambiense human African trypanosomiasis (HAT, sleeping sickness) are often complex due to the unsatisfactory sensitivity and/or specificity of available tests, and typically include a screening (serological), confirmation (parasitological) and staging component. There is insufficient evidence on the relative accuracy of these algorithms. This paper presents estimates of the accuracy of five algorithms used by past Médecins Sans Frontières programmes in the Republic of Congo, Southern Sudan and Uganda. METHODOLOGY AND PRINCIPAL FINDINGS: The sequence of tests in each algorithm was programmed into a probabilistic model, informed by distributions of the sensitivity, specificity and staging accuracy of each test, constructed based on a literature review. The accuracy of algorithms was estimated in a baseline scenario and in a worst-case scenario introducing various near worst-case assumptions. In the baseline scenario, sensitivity was estimated as 85-90% in all but one algorithm, with specificity above 99.9% except for the Republic of Congo, where CATT serology was used as independent confirmation test: here, positive predictive value (PPV) was estimated at <50% in realistic active screening prevalence scenarios. Furthermore, most algorithms misclassified about one third of true stage 1 cases as stage 2, and about 10% of true stage 2 cases as stage 1. In the worst-case scenario, sensitivity was 75-90% and PPV no more than 75% at 1% prevalence, with about half of stage 1 cases misclassified as stage 2. CONCLUSIONS: Published evidence on the accuracy of widely used tests is scanty. Algorithms should carefully weigh the use of serology alone for confirmation, and could enhance sensitivity through serological suspect follow-up and repeat parasitology. Better evidence on the frequency of low-parasitaemia infections is needed. Simulation studies should guide the tailoring of algorithms to specific scenarios of HAT prevalence and availability of control tools.

Dataset Information

The changing epidemiology of human African trypanosomiasis among patients from nonendemic countries--1902-2012.

Background

Methods

Results

Conclusions

Publications

The changing epidemiology of human African trypanosomiasis among patients from nonendemic countries--1902-2012.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets