An outbreak of West Nile Virus infection in the region of Monastir, Tunisia, 2003.
BACKGROUND
A West Nile (WN) fever epidemic occurred in the region of Monastir, Tunisia, between August and October 2003.


OBJECTIVE
We attempt to describe the epidemiology, clinical presentation, and outcome of patients with confirmed West Nile virus (WNV) infection.


METHODS
Three groups of specimens were prepared. One was made up of serum only (n  =  43), the other of cerebrospinal fluid (CSF) only (n  =  30), and the third group was made up of both (n  =  40). These specimens were obtained from 113 patients. A serological diagnosis and evidence of WNV genome by nested reverse-transcriptase polymerase chain reaction (nRT-PCR) and TaqMan reverse transcription-polymerase chain reaction (RT-PCR) were carried out.


RESULTS
Thirty-eight cases (33.6%) were serologically positive. Results of nRT-PCR showed a total of 10 positive cases of WNV (8.8%) detected in group 1 (n  =  1/43), group 2 (n  =  5/30), and group 3 (n  =  4/40) whereas the PCR TaqMan showed 18 positive samples (15.9%) found in group 1 (n  =  3/43), group 2 (n  =  9/30), and group 3 (n  =  6/40). All TaqMan PCR positive cases were nRT-PCR positive. In addition, four serologically probable cases were confirmed by TaqMan PCR. The attempts to isolate WNV by cell culture were unsuccessful. Considering the results of TaqMan assay and the serological diagnosis, WNV infection was confirmed in a total of 42 patients. The main clinical presentations were meningoencephalitis (40%), febrile disease (95%), and meningitis (36%). Eight patients (19%) died. The highest case-fatality rates occurred among patients aged ≧55 years. The phylogenetic analysis revealed that isolates of WNV were closely related to the Tunisian strain 1997 (PAH001) and the Israeli one (Is-98).


CONCLUSIONS
West Nile virus is a reemerging global pathogen that remains an important public health challenge in the next decade.
Samira
S
Riabi
Imed
I
Gaaloul
Maha
M
Mastouri
Mohsen
M
Hassine
Mahjoub
M
Aouni
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood / Q000134:cerebrospinal fluid; D002555:Cerebrospinal Fluid / Q000276:immunology / Q000821:virology; D002648:Child; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood / Q000134:cerebrospinal fluid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D044967:Serum / Q000276:immunology / Q000821:virology; D016019:Survival Analysis; D014416:Tunisia / Q000453:epidemiology; D014901:West Nile Fever / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D014902:West Nile virus / Q000302:isolation & purification*; D055815:Young Adult
D000914:Antibodies, Viral; D012367:RNA, Viral
Epidemiology,; Meningoencephalitis; Outbreak,; TaqMan RT-PCR,; West Nile virus,