The changing malaria landscape in Aseer region, Kingdom of Saudi Arabia: 2000-2015.
BACKGROUND
In 2004, a revised action plan was developed, supported by the World Health Organization, to eliminate malaria from Saudi Arabia by preventing re-introduction of malaria into regions since declared malaria free, eliminating foci of transmission in the Mecca and Medina areas and a concerted effort of foci surveillance and control, to eliminate malaria from the regions of Jazan and Aseer. This paper provides the context, activities, progress, and possible contributions toward malaria elimination in the Aseer region since 2000, with a more detailed analysis of the spatial location of locally acquired case incidence since 2012.


METHODS
This is a descriptive study of all available Ministry of Health surveillance data and process reports since 2000, with higher spatial resolution analysis of data between 2012 and 2015.


RESULTS
In 2000, there were 511 cases of Plasmodium falciparum locally acquired infection. The following 4 years witnessed a dramatic decline in cases to only 18 locally acquired infections reported in 2005. A resurgence in local infections was reported in 2006 (93) and 2007 (165), thereafter (2008-2014) local cases continued to decline to fewer than 40 per year across the region. However, in 2015, a small rise was noted (51). All locally acquired infections were P. falciparum. There has been a constant flow of imported infections into Aseer since 2000, mostly among immigrant labour from Pakistan, India, Sudan, and Yemen. Imported infections have included both Plasmodium vivax and P. falciparum. The spatial extent of malaria appears to be changing, but there remain two intractable areas Sarat Abeda and Dhran Aljanub, where risks per reporting centre have changed little since 2001, remaining above 0.5 per 10,000 population. Only seven villages contributed 55% of all locally acquired infection since 2012.


CONCLUSIONS
Aseer has reached a state of very low incidence of locally acquired infections, despite a constant source of imported infections from outside the country. How many of the local infections are F2 generations from imported infections or how many are a result of residual active transmission between asymptomatic carriers of infections transmitted by pockets of existing Anopheles arabiensis populations remains unknown. A more detailed investigation of the spatial and temporal patterns of infected hosts, parasites and vectors would help define whether this region has managed to effectively prevent local transmission of new infections.
Vector Control Administration, Aseer Health Affairs Directorate, Abha, Kingdom of Saudi Arabia. alidoh@hotmail.com.|Aseer General Directorate of Health Affairs, Abha, Kingdom of Saudi Arabia. alidoh@hotmail.com.
Ali Mohamed
AM
Alshahrani
Vector Control Administration, Aseer Health Affairs Directorate, Abha, Kingdom of Saudi Arabia.|Aseer General Directorate of Health Affairs, Abha, Kingdom of Saudi Arabia.
Tarig M
TM
Abdelgader
Vector Control Administration, Aseer Health Affairs Directorate, Abha, Kingdom of Saudi Arabia.|Aseer General Directorate of Health Affairs, Abha, Kingdom of Saudi Arabia.
Ibrahim
I
Saeed
Vector Control Administration, Aseer Health Affairs Directorate, Abha, Kingdom of Saudi Arabia.|Aseer General Directorate of Health Affairs, Abha, Kingdom of Saudi Arabia.
AbdulRhman
A
Al-Akhshami
Aseer General Directorate of Health Affairs, Abha, Kingdom of Saudi Arabia.
Mohamed
M
Al-Ghamdi
Public Health Directorate, Ministry of Health, Riyadh, Kingdom of Saudi Arabia.
Mohammed H
MH
Al-Zahrani
Public Health and Tropical Medicine, University of Jazan, Jazan, Kingdom of Saudi Arabia.
Ibrahim
I
El Hassan
Spatial Health Metrics Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya.
David
D
Kyalo
Spatial Health Metrics Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya.|Nuffield Department of Clinical Medicine, Centre for Tropical Medicine & Global Health, University of Oxford, Oxford, UK.
Robert W
RW
Snow
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000852:Anopheles / Q000254:growth & development; D002648:Child; D002675:Child, Preschool; D060740:Disease Eradication; D018562:Disease Transmission, Infectious; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000635:transmission; D008297:Male; D008875:Middle Aged; D000072138:Mosquito Vectors / Q000254:growth & development; D012529:Saudi Arabia / Q000453:epidemiology; D062211:Spatio-Temporal Analysis; D014195:Travel; D055815:Young Adult