Emergence of vector-borne diseases during war and conflict

Bereits in archaischer Zeit war der direkte Zusammenhang zwischen Kriegen und dem epidemischen Auftreten von Infektionserkrankungen bekannt und gefürchtet (SMALLMAN-RAYNOR & CLIFF, 2004). Mehr als 100.000 Todesfälle wurden während des Peloponnesischen Krieges 430-426 v.Chr. einer Infektionserkrankung zugeschrieben, bei der es sich höchstwahrscheinlich um das Läusefleckfieber handelte (RETIEF & CILLIERS, 1998). Bewaffnete Konflikte und Kriege führen früher wie heute zu Veränderungen der allgemeinen hygienischen, bevölkerungspolitischen und -dynamischen Situation, einhergehend mit Umwelt- und Verhaltensveränderungen, die erst die Grundlage für das Ausbrechen von Seuchen bieten. Insbesondere bedingt durch gastrointestinale, respiratorische und vektorenübertragene Infektionskrankheiten können die Mortalitätsraten vor allem bei Flüchtlingspopulationen bis um das 60-fache über dem Normalniveau liegen (TOOLE & WALDMANN, 1997). Vektorassoziierte Infektionserkrankungen (VI) wie Läusefleckfieber, Pest, Malaria, Schlafkrankheit und Viszerale Leishmaniose können, je nach Region und endemischem Vorkommen, einen beträchtlichen Anteil an dieser Mortalitätsrate haben und fokal zur Entvölkerung führen (FAULDE, 2001). Von 52 retrospektiv analysierten Kriegen im Zeitraum von ca. 480 v.Chr. bis 2002 wurden in 26 Fällen Leitausbrüche mit VIs festgestellt, davon in 11 Kriegen durch das Läusefleckfieber und in 10 Kriegen durch die Pest (RETIEF & CILLIERS, 1998). Aktuelle Untersuchungen weisen darauf hin, dass in Afrika bis zu einem Drittel der Todesfälle an Malaria bewaffneten Konflikten und Naturkatastrophen zugeschrieben werden kann (ANONYMUS, 2000a). VIs sind seit jeher von Kriegsparteien bewusst oder unbewusst verbreitet worden. Beschrieben wurde das Katapultieren von Pesttoten über die Stadtmauern von Kaffa durch die tartarischen Streitkräfte im Jahr 1346 (MICHELS, 2000) sowie die Initiierung der seit 1983 andauernden, verheerenden Kala Azar-Epidemien mit mehr als 100.000 Todesopfern im Südsudan durch infizierte Truppen aus Endemiegebieten an der sudanesisch-äthiopischen Grenze (NEOUIMINE, 1996). Makabre Bedeutung erlangten biowaffenfähige VIs und Zoonosen wie Anthrax, Pest, Tularämie und Q-Fieber in jüngster Vergangenheit vor allem dadurch, dass sie sich auch für bioterroristische Anschläge eignen können (MICHELS, 2000). Im militärischen Bereich ist die hohe Bedeutung von Infektionserkrankungen im Verlauf von Kriegen und Einsätzen bekannt und findet nach den Erfahrungen während des Zweiten Weltkrieges allgemein Berücksichtigung. Demnach waren im Jahr 1982 von den als militärisch relevant definierten 83 verschiedenen Infektionserkrankungen 53 (ca. 2/3 !) VIs bzw. Zoonosen (FAULDE, 1996). Gerade Auslandseinsätze erhöhen die Gefährdung für Soldaten trotz implementierter präventivmedizinischer Maßnahmen erheblich, an einer VI zu erkranken. Dementsprechend sind in vielen Streitkräften medizinische Entomologen beschäftigt, die primär für die wissenschaftliche Risikoevaluierungen vor Ort, einschließlich der Analyse des Transmissionsmodus sowie der Einleitung und gegebenenfalls auch Durchführung von Vektoren- und Nagetierbekämpfungsmaßnahmen zuständig sind (FAULDE et al., 1994). Erst die bitteren Erfahrungen der letzten Jahre haben bei vielen zivilen Hilfsorganisationen zu nachhaltigen Umdenkprozessen hinsichtlich der VIs geführt. Medizinisch entomologische Ausbildung des Fachpersonals, Risikobewertungen vor den Einsätzen, vektorepidemiologische Erkundung des Einsatzraumes, Vektorenüberwachung, -bekämpfung und -schutz sind insbesondere seit dem Oxfam-Kongress im Dezember 1995 als essentieller Bestandteil medizinischer Unterstützungsleistungen im Nachgang zum internationalen Hilfseinsatz für Ruanda 1994 anerkannt worden (THOMSON, 1995). Ziel der Arbeit ist daher, die ungebrochene Bedeutung der VIs für die betroffene Bevölkerung sowie für zivile Hilfsorganisationen und militärische Stabilisierungs- und Wiederaufbaukräfte an aktuellen Beispielen vorzustellen.Throughout history, the deadly comrades of war and disease have accounted for a major proportion of human suffering and death. During conflict, human populations are often suddenly displaced, associated with crude mortality rates over 60-times higher than baseline rates. Promoting factors like mass movement of populations, overcrowding, no access to clean water, poor sanitation, lack of shelter, and poor nutritional status directly result in rapid increase of infectious diseases, especially measles, respiratory tract infections as well as diarrhoeal and vector-borne diseases. In 26 out of 52 retrospectively analysed wars from 480 B.C. to 2002 A.D., vector-borne diseases like plague, louse-borne typhus, malaria, yellow fever, relapsing fever, scrub typhus, and visceral leishmaniasis prevailed, or essentially contributed to, overall mortality. During the last decades, devastating war-related outbreaks of malaria, louse-borne typhus, trench fever, African sleeping sickness, visceral and cutaneous leishmaniasis and dengue fever have been reported. According to the humanitarian imperative to protect, or to re-establish, the health of the affected population, essential medical entomological expertise has been involved increasingly in complex emergencies in order to analyse transmission modes as well as the epidemiological impact. Adequate countermeasures, such as personal protection against arthropod vectors and vector control efforts have to be initiated and implemented subsequently, aiming at rapid and efficient interruption of transmission cycles. Recent experiences made during emergency situations reveal that more medical entomological expertise and involvement is necessary world-wide to successfully react on future disease threats

Use of mass-participation outdoor events to assess human exposure to tickborne pathogens

Mapping the public health threat of tickborne pathogens requires quantification of not only the density of infected host-seeking ticks but also the rate of human exposure to these ticks. To efficiently sample a high number of persons in a short time, we used a mass-participation outdoor event. In June 2014, we sampled ≈500 persons competing in a 2-day mountain marathon run across predominantly tick-infested habitat in Scotland. From the number of tick bites recorded and prevalence of tick infection with Borrelia burgdoferi sensu lato and B. miyamotoi, we quantified the frequency of competitor exposure to the pathogens. Mass-participation outdoor events have the potential to serve as excellent windows for epidemiologic study of tickborne pathogens; their concerted use should improve spatial and temporal mapping of human exposure to infected ticks

Malaria Reemergence in Northern Afghanistan

Field investigations were conducted in Kundoz Province, an Afghan high-risk area, to determine factors responsible for the rapid reemergence of malaria in that country, where 3 million cases were estimated to have occurred during 2002. Results indicate the presence of nonrice-field–dependent Plasmodium falciparum and rice-field–associated P. vivax malaria

Can interventions that aim to decrease Lyme disease hazard at non-domestic sites be effective without negatively affecting ecosystem health? A systematic review protocol

Background Lyme disease (LD) is the most commonly reported, broadly distributed vector-borne disease of the northern temperate zone. It is transmitted by ticks and, if untreated, can cause skin, cardiac, nervous system and musculoskeletal disease. The distribution and incidence of LD is increasing across much of North America and Western Europe. Interventions to decrease exposure to LD hazard by encouraging behavioural change have low acceptance in high risk groups, and a safe, effective human LD vaccine is not presently available. As a result, habitat level interventions to decrease LD hazard itself (i.e. levels of infected ticks) have been proposed. However, some interventions may potentially negatively affect ecosystem health, and consequentially be neither desirable, nor politically feasible. This systematic review will catalogue interventions that aim to reduce LD hazard at non-domestic sites, and examine the evidence supporting those which are unlikely to negatively affect ecosystem health. Methods The review will be carried out in two steps. First, a screening and cataloguing stage will be conducted to identify and characterise interventions to decrease LD hazard at non-domestic sites. Secondly, the subset of interventions identified during cataloguing as unlikely to negatively affect ecosystem health will be investigated. In the screening and cataloguing step literature will be collected through database searching using pre-chosen search strings, hand-searching key journals and reviewing the websites of public health bodies. Further references will be identified by contacting stakeholders and researchers. Article screening and assessment of the likely effects of interventions on ecosystem health will be carried out independently by two reviewers. A third reviewer will be consulted if disagreements arise. The cataloguing step results will be presented in tables. Study quality will then be assessed independently by two reviewers, using adapted versions of established tools developed in healthcare research. These results will be presented in a narrative synthesis alongside tables. Though a full meta-analysis is not expected to be possible, if sub-groups of studies are sufficiently similar to compare, a partial meta-analysis will be carried out

Cost-effectiveness of adding indoor residual spraying to case management in Afghan refugee settlements in Northwest Pakistan during a prolonged malaria epidemic.

INTRODUCTION: Financing of malaria control for displaced populations is limited in scope and duration, making cost-effectiveness analyses relevant but difficult. This study analyses cost-effectiveness of adding prevention through targeted indoor residual spraying (IRS) to case management in Afghan refugee settlements in Pakistan during a prolonged malaria epidemic. METHODS/FINDINGS: An intervention study design was selected, taking a societal perspective. Provider and household costs of vector control and case management were collected from provider records and community survey. Health outcomes (e.g. cases and DALYs averted) were derived and incremental cost-effectiveness ratios (ICERs) for cases prevented and DALYs averted calculated. Population, treatment cost, women's time, days of productivity lost, case fatality rate, cases prevented, and DALY assumptions were tested in sensitivity analysis. Malaria incidence peaked at 44/1,000 population in year 2, declining to 14/1,000 in year 5. In total, 370,000 malaria cases, 80% vivax, were diagnosed and treated and an estimated 67,988 vivax cases and 18,578 falciparum and mixed cases prevented. Mean annual programme cost per capita was US$0.56. The additional cost of including IRS over five years per case prevented was US$39; US$50 for vivax (US$43 in years 1-3, US$80 in years 4-5) and US$182 for falciparum (US$139 in years 1-3 and US$680 in years 4-5). Per DALY averted this was US$266 (US$220 in years 1-3 and US$486 in years 4-5) and thus 'highly cost-effective' or cost-effective using WHO and comparison thresholds. CONCLUSIONS: Adding IRS was cost-effective in this moderate endemicity, low mortality setting. It was more cost-effective when transmission was highest, becoming less so as transmission reduced. Because vivax was three times more common than falciparum and the case fatality rate was low, cost-effectiveness estimations for cases prevented appear reliable and more definitive for vivax malaria

Risk Factors for Anthroponotic Cutaneous Leishmaniasis at the Household Level in Kabul, Afghanistan

Cutaneous leishmaniasis is a vector-borne protozoan disease that is characterized by cutaneous lesions which develop at the site of the insect bite. Lesions can vary in severity, clinical appearance, and time to cure; in a proportion of patients lesions can become chronic, leading to disfiguring mucosal leishmaniasis or leishmaniasis recidvans. Albeit not fatal, cutaneous leishmaniasis can have a significant social impact as it may lead to severe stigmatisation of affected individuals when lesions or scars occur on the face and exposed extremeties. Over the last 10–20 years there has been an increase in the number of leishmaniasis cases reported in South Asia, particularly in Afghanistan. Little is known about the household-level risk factors for infection and disease. Here we confirm previous reports that had shown the association of cutaneous leishmaniasis with age and clustering of cases at the household-level. Additionally, we show that risk of cutaneous leishmaniasis is associated with household construction (i.e. brick walls) and design (i.e. proportion of windows with screens)

Genetic Polymorphisms and Drug Susceptibility in Four Isolates of Leishmania tropica Obtained from Canadian Soldiers Returning from Afghanistan

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease transmitted by the bite of sandflies, resulting in sores on the skin. No vaccines are available, and treatment relies on chemotherapy. CL has been frequently diagnosed in military personnel deployed to Afghanistan and returning from duty. The parasites isolated from Canadian soldiers were characterized by pulsed field gels and by sequencing conserved genes and were identified as Leishmania tropica. In contrast to other Leishmania species, high allelic polymorphisms were observed at several genetic loci for the L. tropica isolates that were characterized. In vitro susceptibility testing in macrophages showed that all isolates, despite their genetic heterogeneity, were sensitive to most antileishmanial drugs (antimonials, miltefosine, amphotericin B, paromomycin) but were insensitive to fluconazole. This study suggests a number of therapeutic regimens for treating cutaneous leishmaniasis caused by L. tropica among patients and soldiers returning from Afghanistan. Canadian soldiers from this study were successfully treated with miltefosine

Thrombocytopenia and Acute Renal Failure in Puumala Hantavirus Infections

Low platelet counts are a novel predictive marker suitable for risk-adapted patient management