Risk assessment for yellow Fever in Western and north-Western provinces of zambia.
BACKGROUND
North-Western and Western provinces of Zambia were reclassified as low-risk areas for yellow fever (YF). However, the current potential for YF transmission in these areas is unclear.


OBJECTIVE
To determine the current potential risk of YF infection.


METHODS
A cross sectional study was conducted in North-Western and Western provinces of Zambia.


METHODS
Samples were tested for both YF virus-specific IgG and IgM antibodies by the ELISA and YF virus confirmation was done using Plaque Reduction Neutralization Test. The samples were also tested for IgG and IgM antibodies against other flaviviruses.


RESULTS
Out of the 3625 respondents who participated in the survey, 46.7% were males and 9.4% were aged less than 5 years. Overall, 58.1% of the participants slept under an impregnated insecticide-treated net and 20.6% reported indoor residual spraying of insecticides. A total of 616 (17.0%) samples were presumptive YF positive. The prevalence for YF was 0.3% for long-term infection and 0.2% for recent YF infection. None of the YF confirmed cases had received YF vaccine. Prevalence rates for other flaviviruses were 149 (4.1%) for Dengue, 370 (10.2%) for West Nile and 217 (6.0%) for Zika.


CONCLUSIONS
There is evidence of past and recent infection of YF in both provinces. Hence, they are at a low risk for YF infection. Yellow fever vaccination should be included in the EPI program in the two provinces and strengthen surveillance with laboratory confirmation.
Zambia Country Office, World Health Organization, Lusaka, Zambia.
Olusegun A
OA
Babaniyi
Permanent Secretary Office, Ministry of Home Affairs, Lusaka, Zambia.
Peter
P
Mwaba
Department of Clinical Sciences, School of Medicine, Copperbelt University, Ndola, Zambia.
David
D
Mulenga
Department of Pathology and Microbiology, University Teaching Hospital, Lusaka, Zambia.
Mwaka
M
Monze
Department of Disease Prevention and Control, World Health Organization, Lusaka, Zambia.
Peter
P
Songolo
Department of Pathology and Microbiology, University Teaching Hospital, Lusaka, Zambia ; Department of Immunization Vaccines and Emergencies, World Health Organization, Lusaka, Zambia.
Mazyanga L
ML
Mazaba-Liwewe
Department of Pathology and Microbiology, University Teaching Hospital, Lusaka, Zambia ; Department of Immunization Vaccines and Emergencies, World Health Organization, Lusaka, Zambia.
Idah
I
Mweene-Ndumba
Department of Malaria, World Health Organization, Lusaka, Zambia.
Freddie
F
Masaninga
Department of Public Health Surveillance and Research, Ministry of Health, Lusaka, Zambia.
Elizabeth
E
Chizema
Department of Inter-country Support Team, World Health Organization, Harare, Zimbabwe.
Messeret
M
Eshetu-Shibeshi
Department of Public Health Surveillance and Research, Ministry of Health, Lusaka, Zambia.
Costantine
C
Malama
Deans Office, School of Health Professions, Andrews University, Michigan, USA.
Emmanuel
E
Rudatsikira
Department of Clinical Sciences, School of Medicine, Copperbelt University, Ndola, Zambia ; Department of Public Health, School of Health Sciences, University of Lusaka, Lusaka, Zambia.
Seter
S
Siziya
Prevalence; Western and North-Western provinces; Zambia; yellow fever