Co-circulation of Toscana virus and Punique virus in northern Tunisia: a microneutralisation-based seroprevalence study.
BACKGROUND
In northern Tunisia, the co-circulation of two related sand fly-borne phleboviruses, Toscana virus (TOSV) and Punique virus (PUNV) was previously demonstrated. In contrast to TOSV, a prominent human pathogen, there is no data supporting that PUNV is capable to infect and cause disease to humans. We studied the respective involvement of TOSV and PUNV in human infections in northern Tunisia through a seroprevalence study.


METHODS
The presence of TOSV and PUNV neutralising antibodies (NT-Ab) was tested in human sera collected from 5 districts of the governorate of Bizerte, and the titres of NT-Ab were estimated by microneutralisation (MN) assay.


RESULTS
A total of 1,273 sera were processed. TOSV and PUNV NT-Ab were detected in 522 (41%) and 111 sera (8.72%) respectively. TOSV seroprevalence varied from 17.2% to 59.4% depending on the district. Analysis of TOSV geometric mean titre values demonstrated a constant increase according to the age. The vast majority of sera containing NT-Ab were found to be more reactive toward TOSV than PUNV. Indeed, past infections with PUNV and TOSV were undisputable for 5 and 414 sera, respectively.


CONCLUSIONS
PUNV may be capable to infect humans but at a low rate. TOSV is responsible for the vast majority of human infections by sand fly-borne phleboviruses in northern Tunisia. TOSV must be considered by physician and tested in diagnostic laboratories for patients with meningitis and unexplained fever in northern Tunisia.
Institut Pasteur de Tunis, Tunis, Tunisia.
Sonia
S
Sakhria
Laurence
L
Bichaud
Mohamed
M
Mensi
Nicolas
N
Salez
Khalil
K
Dachraoui
Laurence
L
Thirion
Saifedine
S
Cherni
Ifhem
I
Chelbi
Xavier
X
De Lamballerie
Elyes
E
Zhioua
Rémi N
RN
Charrel
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009500:Neutralization Tests; D010217:Phlebotomus Fever / Q000453:epidemiology* / Q000821:virology*; D029301:Sandfly fever Naples virus / Q000302:isolation & purification*; D016036:Seroepidemiologic Studies; D014416:Tunisia / Q000453:epidemiology; D055815:Young Adult
D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral