Odyssean malaria outbreak at a bush lodge in Madikwe Game Reserve, North West Province, October-November 2015 Genevie Ntshoe, Andrew Tlagadi, Thejane Motladiile, Kerrigan McCarthy, Oleteng Mokate, John Frean FIDSSA 2017 9-11 November 2017
Introduction Malaria endemic in 3 of 9 provinces in South Africa KwaZulu-Natal, Limpopo and Mpumalanga North-eastern parts & lowveld areas Cases also reported in non-endemic provinces Imported malaria acquisition in known transmission areas Odyssean malaria acquired through bite of an imported Anopheles spp. mosquito in people whose geographic history firmly excludes exposure to vector in malaria endemic areas Most cases due to Plasmodium falciparum Disease seasonal, occurring during rainy months: October to May Peak January April Most notified malaria cases in North West Province (NWP) imported However, odyssean malaria cases also reported
11 November 2015: malaria case notified to Outbreak Response Unit, National Institute for Communicable Diseases (NICD) Case identified at bush lodge, Madikwe Game Reserve, NWP Area outside recognised endemic malaria transmission in South Africa Some other people with fever, headache, flu-like illnesses reported Investigation to determine possible cause of illness undertaken Four employees with malaria No travel history to malaria endemic areas Background Collaborative field investigation conducted on 9 December 2015 NICD, NWP Health Department & Bojanala District
Objectives To describe characteristics of laboratory-confirmed malaria cases To identify undiagnosed malaria cases amongst employees and management at the lodge To detect possible asymptomatic infection To establish if there were breeding sites for mosquitoes If possible collect and identify mosquito vectors of malaria To identify possible source/s
Case definitions Suspected case Person presenting with fever, headache and/or flu-like illness where no obvious cause was evident, at the lodge during September to November 2015 Laboratory-confirmed case A suspected case in whose blood smear malaria parasites were observed and/or whose malaria rapid antigen test was positive Asymptomatic infection Presence of malaria parasites in the blood (by PCR or smear microscopy or antigen test positive) in a person with no malaria symptoms at the time of venesection
Methods Epidemiological investigation Where consent granted, interviews conducted with staff members Structured questionnaire used to gather information on demographic, clinical & exposure history Lodge management interviewed to gather information about guests who visited the area before staff members became ill Laboratory investigation EDTA-anticoagulated blood samples collected Blood smear microscopy & PCR analysis for detection of malaria parasites conducted at CEZPD (Parasitology Reference Laboratory), NICD Environmental investigation Environmental assessment of residence & immediate surroundings conducted To identify possible breeding sites for mosquitoes Intervention measures Health education/promotion activities Distribution of information pamphlets Personal protection against mosquito bites
Results Epidemiological and clinical findings 33 staff members interviewed Travel history to possible malaria transmission area reported (n=8) Mpumalanga (n=6) Bushbuckridge (n=4) Kruger National Park (n=2) Zimbabwe (n=2) Guests: Aug to Oct 2015 10 groups visited the lodge No travel history to/from malaria endemic areas (n=6) One group from Zimbabwe Date of visit 11-14 Oct Travel history not available (n=3) Travel history of staff members to possible malaria transmission areas Date of Travel Area travelled to Number of people 29 August to 11 September 2015 Bushbuckridge 3 13 to 24 September 2015 Kruger National Park 2 27 September to 14 October 2015 Zimbabwe 1 28 September to 16 October Zimbabwe 1 2 to 15 October 2015 Bushbuckridge 1
Results Epidemiological and clinical findings Oct-Nov 2015: Four laboratory-confirmed cases identified All female, age range 27 55 years None had travel history to malaria endemic areas No recent blood transfusions reported 3 housekeepers and 1 chef All resided at staff residences Case 1 & 2 rooms next to each other Case 3 & 4 shared a room Most reported symptoms Fever, headache, dizziness, painful points Diarrhoea, fatigue, nausea, flu-like illness Vomiting Two admitted to hospital All four recovered
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 2 4 6 8 10 Number of cases Epidemic curve illustrating number of cases by date of onset of symptoms, 1 September to 10 December 2015 with return dates of travel from malaria endemic areas* 5 4 Case 1 symptoms onset 3 Case 2 symptoms onset 2 1 3 staff members return from possible malaria transmission area 2 staff members return from possible malaria transmission area Case 3 & 4 symptoms onset 1st case reported to NICD 0 Site visit Sep Oct Nov Dec Date of onset * Travellers returning from malaria endemic areas outside incubation period not included
Results Environmental findings Lodge in close proximity to Marico River Staff residences within 50-60 m of parking bay Pyrethroid-based insecticide used for spraying No evidence of free-standing water to enable mosquito breeding Besides Marico River and swimming pools Laboratory findings Blood samples collected from 32/33 Microscopy and PCR analysis negative on all samples tested
Discussion and conclusions Describe what appears to be an odyssean malaria outbreak Delay in malaria diagnosis No information or evident history of travel to a malariaendemic/transmission area among all case-patients No additional malaria cases/asymptomatic infections identified, nor in the local/district municipality Based on date of onset of symptoms, incubation period and date/s of travel to possible malaria transmission areas: Most likely case-patients acquired malaria from bite of an infective Anopheles mosquito inadvertently translocated from a malaria endemic area by vehicle or individual carrying it in a bag/suitcase
Discussion and conclusions Parking bay few metres away from staff residences - could plausibly have been release site of the mosquito/es Malaria vector mosquitoes can Fly an estimated distance of up to 1.5 km Survive about 4 weeks in favourable environment & weather conditions During that time potentially infect multiple people, even in one night Most likely vehicle to have transported mosquito/es One arriving from Kruger Park on 24 September 2015 Likely that same infected mosquito/es could have infected all case-patients However - case 3 & 4, based on date of onset of symptoms (22 October 2015 in both cases), given they shared a room - highly likely infected by same mosquito
Limitations We could not conduct a detailed entomological assessment to rule out presence of malaria mosquito vectors in the area None of the entomologists available during site visit Investigation team not trained or equipped to do so Unable to collect mosquitoes for investigation or identify species
Recommendations Spraying of interiors of vehicles arriving from malaria endemic areas using appropriate insecticides would reduce risk of transporting vector mosquitoes Difficult to apply or enforce on arrival Spraying vehicles before departure may be more effective To avoid mosquito bites, staff members encouraged to use insect repellents, mosquito coils, wear long-sleeved clothing & socks in the evenings Managers at lodge & healthcare workers in area alerted to existence of cases To increase awareness for subsequent cases Advise to maintain high index of suspicion for malaria in individuals presenting with fever, headache & flu-like illness Where no obvious cause evident In whom no recent travel history to malaria transmission area forthcoming Minimise potential mosquito breeding sites Ensure no temporary bodies of water in the area
Acknowledgements Staff and management of the establishment North West Provincial and District Department of Health Environmental Health Practitioners Communicable Disease Control Coordinators Outbreak Response Teams Local health authorities/healthcare workers National Institute for Communicable Diseases Parasitology and Vector Control Reference Laboratories Outbreak Response Unit South African Field Epidemiology Training Programme
Thank you!