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| Malaria epidemiological profile September 1999 |
| EAST AND WEST TIMOR |
| Type of complex emergency: massive displacement of populations in East Timor, including movements between East and West Timor. Disruption of health services. Pre-existing vulnerability of population with malnutrition and anaemia. |
| East Timor | West Timor | |
| Basic indicators Total population (1998) IMR (1997) CDR (1996) Iron deficiency anaemia (1992) |
875,989 70 99 48.0 (pregnant women) 40.7 (under fives) |
1,452,153
54 82 59.7 (pregnant women) 63.4 (under fives) |
| Plasmodium species |
60-80% P.falciparum, remainder P.vivax and very sporadic P.ovale |
|
| Malaria cases detected (1998) % OPD attendance due to Parasite rate (population) *1 Slide positivity rate (1998) |
10,332
confirmed malaria cases out of total 21,782 slides examined
12.25 varying from 10% in Ermera to 55% in Dili to 73% in Manufahi district, with average SPR for East Timor at 49% |
9,667
confirmed malaria cases out of total 25,604 slides examined
37% on average |
| General epidemiological characteristics |
Rainfall and
temperature are favourable for perennial malaria transmission. Transmission intensity
depends on altitude and different vector habitats. Resulting endemicity can be summarised
as hyperendemic, with a few limited spots reported to be holoendemic in the plains,
decreasing at higher altitudes to meso-endemic, hypoendemic and non-malarious. The immune
status of the adult population and thus the likely severity of a clinical malaria attack
in these people will depend on previous exposure. Due to the population movement and destruction of services, man-vector contact will be increased, mosquito breeding may increase, and there will be delays in finding effective treatment for malaria disease. These will likely result in increased transmission and increasing severe disease and mortality. Variability in immune status is to be expected in population groups originating from different parts of East Timor. |
|
| Main high risk groups | Displaced and malnourished populations, with highest risk of death in young children and pregnant women | |
| Antimalarial drug sensitivity | East Timor | West Timor |
| In vitro resistance
reported to the following drugs: - Chloroquine - Amodiaquine - Sulfadoxine/pyrimethamine |
In vitro resistance
reported to the following drugs: - Chloroquine - Amodiaquine - Sulfadoxine/pyrimethamine Recent therapeutic efficacy test (n=22) showed 95% adequate clinical response to chloroquine |
|
| Potential for epidemics | Increased malaria transmission with increased morbidity and mortality can be expected within the next few weeks. | Malaria transmission linked to the wet season, mostly in Oct./Nov. – March/April. |
| Recent malaria control measures in West and East Timor | The objective has been to reduce
morbidity and prevent/reduce mortality, particularly in priority areas of transmigration
and socio-economic development projects covering 10-15% of the population, through: - passive case detection through hospitals and clinics - malariometric surveys - treatment with 1st line chloroquine, 2nd line SP, 3rd line quinine - prophylaxis with chloroquine - indoor residual spraying, two rounds per year, with lambdacyhalothrin - biological control with guppy fish - insecticide treated bednets - larviciding with Bacillus thuringiensis H-14 - environmental management - early warning system and outbreak control - training - health education In recent years, the implementation of control interventions has been affected by the economic crisis. |
| Vector species | Timor has more than one species
of malaria vector. Some breed in brackish/saline water collections in coastal areas (An
sundaicus), others in rice fields, irrigation canals and slow-moving hilly streams
(potential vector An aconitus), others occur in coastal and inland areas (An
subpictus). An barbirostris, due to its widespread occurrence on the island
is likely to be the main vector. Biting and resting habits, man-preference, and seasonal
abundance of these four vector species differ. As a result, different seasonal
transmission peaks occur on different parts of the island. Vector control interventions, including the use of indoor residual spraying or insecticide treated bednets, should be guided by entomological expertise to be most effective. |
| Insecticide resistance | The use of DDT is banned in the
country. Recent data from Flores indicate that the local vector is susceptible to pyrethroids. Choices of effective insecticides for indoor residual spraying include pyrethroids, organophosphates and carbamates. Pyrethroids can be used for insecticide impregnated mosquito nets. |
| Key contacts: | Specific control interventions
need an assessment of the current situation on the ground. Further updates to this
briefing note will be made available. In the meantime, specific information on issues
relating to the treatment of malaria disease and epidemic control interventions can be
obtained from the WHO Regional and Country offices: - Dr P.R. Arbani, Regional Malaria Adviser, WHO Regional Office for the South-East Asian Region in Delhi, India, at email arbanip@whosea.org- Dr G. Petersen, WHO Country Representative for Indonesia, in Jakarta, at email petersen@who.or.id |
Recommended malaria prophylaxis and stand-by treatment
for
international staff travelling to East Timor *2
Rationale for choice of drugs: Under normal circumstances, chloroquine plus proguanil would be the recommended malaria prophylaxis. However, at present there are large-scale population movements and a destruction of services, including malaria control interventions, combined with an influx of non-immune foreigners in East Timor. These circumstances favour the spread and increase of both malaria transmission and antimalarial drug resistance. P.falciparum highly resistant to chloroquine and resistant to sulfadoxine/pyrimethamine has already been reported in East Timor. Under these circumstances, chemoprophylaxis with mefloquine or doxycycline is preferable to regimens containing chloroquine.
Recommended prophylaxis: mefloquine OR doxycycline
Emergency stand-by treatment: quinine OR – when on doxycycline prophylaxis – mefloquine.
General comments:
Mefloquine prophylaxis should be started at least one week before entering the endemic area. Doxycycline prophylaxis should be started the day before entering the endemic area. Chemoprophylaxis should be continued with unfailing regularity throughout the stay in Timor, and for 4 weeks after leaving the endemic area.
Chemoprophylaxis does not offer 100 % protection, and staff should be alert to the possibility of a clinical attack of malaria, which may appear as early as 7 days after entering the endemic area. Falciparum malaria, which can be fatal, must always be suspected if fever, with or without other symptoms, develops at any time between one week after the first possible exposure and 2 months (or even later in rare cases) after the last possible exposure. Staff should be informed that malaria can kill if treatment is delayed beyond 24 hours, and that medical help must be sought promptly if a febrile illness occurs. A blood sample should be taken and examined for malaria parasites on one or more occasions.
Staff should be informed on how to protect themselves against mosquito bites.
Most international staff will be able to obtain prompt medical attention when malaria is suspected. However, some may be unable to seek such care within 24 hours of the onset of symptoms, particularly if they are in an isolated location far from medical services. In such cases, it is advised that prescribers issue antimalarial drugs to be carried by the staff for self-administration ("stand-by emergency treatment"). Staff prescribed stand-by emergency medication should be given precise instructions on the recognition of symptoms, the treatment regimen, possible side-effects, and the action to be taken in the event of drug failure. Self-treatment is a first-aid measure, and they should seek medical advice as soon as possible. Mefloquine prophylaxis should only be resumed 7 days after the last self-treatment dose of quinine. Doxycycline prophylaxis can be resumed immediately.