Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 10  |  Issue : 1  |  Page : 28-31  

Flea outbreak at United Nations base in South Sudan: A public health challenge


Department of Community Medicine, Armed Forces Medical College, Pune, Maharashtra, India

Date of Web Publication9-Jan-2017

Correspondence Address:
Dr. Anuj Bhatnagar
Department of Community Medicine, Armed Forces Medical College, Pune - 411 040, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-2870.197898

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  Abstract 

Background: A large number Indian troops are deployed in International Peacekeeping Missions Worldwide and are exposed to emerging and re-emerging vectors and diseases in unfamiliar terrain. This article describes the experience of a flea outbreak among Indian UN Peacekeepers in a remote part of South Sudan. Methods: Health visits to the area confirmed presence of dog fleas. Flea bites disrupted daily routine of the unit and many troopers reported to medical facilities with severe dermatitis. Death of a field rat in the immediate vicinity along with detection of rat fleas was cause for worry as Plague and other flea-borne diseases are known to occur in the country in sylvatic form. Result: Conventional vector control measures had limited impact and unconventional measures had to be devised due to limited capacity in the inaccessible area. Severity of the problem, potential to cause flea-borne diseases and unavailability of conventional insecticides prompted the author to use Aviation Turbine Fuel (ATF) for area spray in the UN base. Conclusion: Healthcare providers in fast-evolving operational situations such as Peacekeeping Missions need to maintain high index of suspicion and often adopt innovative methods to ensure effective public health cover to troops.

Keywords: Flea-borne diseases, flea outbreak, United Nations peacekeeping mission


How to cite this article:
Bhatnagar A, Kaushik S K. Flea outbreak at United Nations base in South Sudan: A public health challenge. Med J DY Patil Univ 2017;10:28-31

How to cite this URL:
Bhatnagar A, Kaushik S K. Flea outbreak at United Nations base in South Sudan: A public health challenge. Med J DY Patil Univ [serial online] 2017 [cited 2024 Mar 28];10:28-31. Available from: https://journals.lww.com/mjdy/pages/default.aspx/text.asp?2017/10/1/28/197898


  Introduction Top


Controlling vectors of medical interest by armed forces remains a challenging task because of close contact with wildlife, fast evolving scenarios, and limited resources available in operational settings. Fleas constitute a major threat as disease vectors and controlling them in field areas still remains an elusive goal for public health specialists, worldwide. Although plague remains the most commonly known disease transmitted by fleas, several re-emerging flea-borne diseases are gaining importance because of our inability to expect, identify and control such diseases in time. These include endemic typhus (Rickettsia typhi), cat scratch disease (Bartonella henselae), flea-borne spotted fever (Rickettsia felis), tungiasis (Tunga penetrans), chiggerosis, and helminths such as Dipylidium caninum, Hymenolepis diminuta, and Hymenolepis nana.

Flea-borne diseases have always been of special interest to the armed forces, especially in situ ations of internal strife where there are large numbers of internally displaced people (IDP). South Sudan is one such scenario where large number of IDPs live in abject poverty and overcrowding in unsanitary conditions in various IDP camps, often located inside or in close proximity to base camps of United Nations (UN) peacekeeping mission in view of its mandate to protect civilians.


  Reporting of an Adverse Event Top


On 15 November 2012, telephonic intimation was received from medical officer of a UN base on the Northeastern border of South Sudan about excessive insect bites among Indian troops deployed as Peacekeepers as part of UN Mission in South Sudan (UNMISS). Preliminary reports indicated insect bites among troops, with exacerbation in the past 48 h subsequent to death of two canine pups under one of the shelters. The insects were identified by Regimental Medical Officer (RMO) as fleas based on naked eye examination and circumstantial evidence of heavily infested carcasses of dead pups. Samples of insects collected by troops from inside various living accommodations were called for by the author for investigation. A total of 165 live fleas and 58 dead fleas were brought by various peacekeepers to the worker over a period of 3 days, having caught them from inside dwelling units, which was considered unusually high. Quantitative flea indices before and after the intervention were not calculated due to exceptional field scenario and the need to institute immediate control measures. On microscopic examination, majority were found to be dog fleas (Ctenocephalides canis) based on morphological structure, which though primarily of biting nuisance to man, are also intermediate hosts of certain veterinary cestodes, like dog tapeworm and have also been implicated in plague epidemiology in Africa. Among the specimens received was also found one specimen of rat flea – Xenopsylla (Xenopsylla cheopis/brasiliensis), which is an important vector of plague in Africa. The finding of rat flea among a large number of dog fleas, collected indoors at night by the troops themselves, was considered unusual in itself warranting urgent public health visit to the site by the author.


  Salient Epidemiological Findings Top


The following public health issues were identified:

  1. Explosive outbreak of flea population resulting in flea bites among troops, causing severe dermatitis, itching, and allergic reactions among troops [Figure 1]
  2. Excessive infestation of the general area with fleas. During night, bites were severe enough to cause significant distress and lack of sleep, even inside living accommodations
  3. Minimal effect of repellent creams on fleas, due to high ambient temperature and humidity
  4. Maximum infestation in shelters, where carcasses of two infested canine pups were recovered
  5. Presence of a large number of Nile rats and domiciliary rats in the area
  6. Two UN High Commissioner for Refugees camps close to the UN base with sizeable population of IDPs.
Figure 1: Flea bite causes a delayed type of skin reaction, which starts as a hemorrhagic punctuate area on the site the flea probes for a blood meal. Lesions often occur in clusters due to repeated probing by the flea. A wheal is formed around each bite and pruritis is invariably present. The flea bite forms a hardened papillar lesion within 12–24 h. Severe itching at the sites of flea bite, usually on lower limbs and exposed parts of the body, is the reason to report to the hospital

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  Prevention and Control Measures Top


The following public health actions were initiated:

  1. Intensive health education of troops about personal protective measures to be taken at individual level, such as compulsory wearing of long trousers tucked into boots and long-sleeved shirts, especially during cooler hours of the day when flea biting rate is highest
  2. Indoor residual spray in all accommodation and offices, using deltamethrin 2.5%
  3. Space spray outside living accommodation and offices, with Pyrethrum 0.1%
  4. Compulsory use of insecticide-treated bednets at night and during daytime while resting, to prevent flea bites
  5. High levels of sanitation and barrack cleanliness with a view to deny shelter to fleas
  6. Denial of shelter and food to dogs and cats in the UN base so that they leave the infested area. Killing of dogs and cats was strongly discouraged as fleas leave the dead body of the host immediately after death due to fall in body temperature, and seek new hosts such as humans, in search of fresh blood meal
  7. Area cleanliness in UN base, removal of debris and minor engineering measures like filling up of rat burrows.


Subsequently, fresh carcass of a young and apparently healthy Nile rat, heavily infested with fleas, was found in the area. On combing the carcass, few fleas were isolated, which were identified as Xenopsylla spp [Figure 2].
Figure 2: Flea isolation from dead field rat in field location

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  Discussion Top


Explosive outbreak of fleas at an Indian UN base in South Sudan was reported, with extensive flea bites among troops, causing skin symptoms among troops warranting medical consultation at the Field Hospital, located more than 300 km away. Identification of rat flea among specimens collected indoors prompted an emergent public health response. The alarming discovery of fresh carcass of a young heavily-infested field rat, without evidence of any predator attack or rodenticidal action, could well be the index case of “rat fall,” which is “sudden unexplained death of apparently young healthy rats infested with rat fleas” and is historically known to precede onset of bubonic plague among humans. Hence, a close watch was kept and all personnel at the UN base were briefed in detail to immediately report any more instances of dead field rats found in the area. Active killing of rats was strongly discouraged since fleas would then attack humans in greater numbers in search of blood meals.

There was significant movement of personnel through the remote infested UN base, which was mostly air-maintained. The possibility of transportation of fleas on clothing, person or in cargo from the infested site to newer areas and subsequent infestation of newer areas in UNMISS could not be ruled out. The extensive scale and extent of flea infestation warranted control measures to be initiated on emergent basis, to prevent buildup of flea population and any likely outbreak of flea-borne diseases among UN peacekeepers locally and their spread to other areas in UNMISS. For optimal utilization of limited resources, it was considered prudent to focus control measures only to the infested areas in the UN Base.

In view of the acute shortage of conventional insecticides and to augment the effect of control measures highlighted earlier, outdoor area spray of the UN base with kerosene oil, in and around the rodent burrows was also recommended. However, in the absence of kerosene oil in UN inventory, aviation turbine fuel (ATF), available readily as fuel for UN flights, was used, (which is kerosene-based fuel, classified as JET-A1) and was found effective.

Over next 15 days, insecticide-based control measures, stringent personal protective and minor engineering measures were undertaken, and the flea population was controlled. The area was kept under close supervision for the next 30 days. The aim of control measures was to reduce flea density as quickly as possible, institute locally sustainable control measures, and interrupt any possible transmission between various definitive/accidental hosts.

ATF is kerosene-based fuel for aircraft jet engines and its use in the present scenario was resorted to at the remote UN base due to exceptionally harsh logistic field circumstances where there was total disruption of all forms of supply channels in a war-torn country and flea menace among international peacekeepers was significant to warrant institution of emergent public health measures by the worker. As such, most insecticides used routinely in field are either kerosene-based or diesel-based and have higher combustibility. Even kerosene is an established anti-arthropod agent and has been used extensively in the past.[1],[2],[3] Thus, ATF was not found to pose any higher threat to humans as compared to other routinely used kerosene-based or diesel-based insecticide preparations. Although kerosene is an established anti-arthropod agent, ATF (which is kerosene-based fuel) has not been used for vector control due to cost considerations. This experience highlights the innovative use of ATF, complemented by minor engineering methods, for flea control at the remote UN base camp, tried out successfully in the absence of routinely recommended insecticides.

Plague is endemic in Northeastern regions of Ituri River and western banks of Lake Albert which have borders with South Sudan. Seroprevalence of  Yersinia More Details pestis is already established among dogs and cats in the region bordering South Sudan.[4] The Nile rat, found abundantly in all regions of the country, is a known reservoir of plague [5] and transmits the infection to domiciliary black rats. Last few decades have witnessed the highest incidence of plague from Africa and involvement of dogs in plague epidemiology is well established in parts of Africa.[6],[7] Such infections hold the potential to re-emerge as epidemics among susceptible human populations, namely, peacekeeping personnel. The threat is further exacerbated by the fact that healthcare professionals in peacekeeping missions are likely to be unaware of presence of reservoir of such diseases and thus do not take into consideration the several flea-borne diseases while treating patients. In addition, health administrators, in the absence of any major epidemics or outbreaks, often fail to allocate adequate funds, manpower, and resources for surveillance of flea-borne diseases. UN peacekeeping missions in various parts of the world present unique challenges to health-care providers of Indian armed forces. As re-emerging diseases, they pose a major public health challenge and in the absence of timely intervention, have the potential to cause outbreaks. In the present case, although there were no confirmed cases of flea-borne infections among the peacekeepers, it is notable that all fever cases were treated empirically on site by the RMO and doxycycline was one of the antibiotics often used. With on-going sylvatic transmission of several flea-borne diseases, including plague and documented outbreaks in the neighboring areas, it is only a matter of time when the enzootic transmission assumes an epidemic form in human populations in the area. It is imperative for all health-care administrators in UN missions to be aware of the real threat posed by flea-borne diseases, especially when operating in new, unknown and uncharted territories and accordingly prepare and empower the health providers with the equipment, chemicals, and drugs to face any outbreak of flea-borne diseases.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Heukelbach J, Mencke N, Feldmeier H. Editorial: Cutaneous larva migrans and tungiasis: The challenge to control zoonotic ectoparasitoses associated with poverty. Trop Med Int Health 2002;7:907-10.  Back to cited text no. 1
    
2.
Diaz JH. The epidemiology, diagnosis, management, and prevention of ectoparasitic diseases in travelers. J Travel Med 2006;13:100-11.  Back to cited text no. 2
    
3.
Heukelbach J, de Oliveira FA, Hesse G, Feldmeier H. Tungiasis: A neglected health problem of poor communities. Trop Med Int Health 2001;6:267-72.  Back to cited text no. 3
    
4.
Davoust B, Diatta G, Shako JC, Rajerison M, Abedi AA, Karhemere S, et al. Seroprevalence of Yersinia pestis in dogs and small rodents in one hyperendemic plague focus of Democratic Republic of Congo. Afr J Microbiol Res 2013;7:1622-4.  Back to cited text no. 4
    
5.
Davis DH. Plague in Africa from 1935 to 1949; a survey of wild rodents in African territories. Bull World Health Organ 1953;9:665-700.  Back to cited text no. 5
    
6.
Borchert JN, Mach JJ, Linder TJ, Ogden-Odoi A, Angualia S. Invasive rats and bubonic plague in Northwest Uganda. Managing Vertebrate Invasive Species; 2007. p. 282-93. http://digitalcommons.unl.edu/nwrcinvasive/?utm_source=digitalcommons.unl.edu%2Fnwrcinvasive%2F3&utm_medium=PDF&utm_campaign=PDFCoverPages. [Last accessed on 2016 Jul 18].  Back to cited text no. 6
    
7.
Kilonzo BS, Gisakanyi ND, Sabuni CA. Involvement of dogs in plague epidemiology in Tanzania. Serological observations in domestic animals in Lushoto District. Scand J Infect Dis 1993;25:503-6.  Back to cited text no. 7
    


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Abstract
Introduction
Reporting of an ...
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