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Wes Nile Vi us Exposu e in Sudan: A C oss-Sec ional S udy (2019–2022)
Sa a Elsadig Elagib El ahi *, Abd El Rahman Aldaw Mohammed and Ome Hassan Mohamed
Facul y o Medical Labo a o y Sciences, Uni e si y o Gezi a, Sudan.
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
Publica ion his o y: Recei ed on 14 Sep embe 2025; e ised on 22 Oc obe 2025; accep ed on 25 Oc obe 2025
A icle DOI: h ps://doi.o g/10.30574/gscbps.2025.33.1.0406
Abs ac
Wes Nile i us (WNV) is a mosqui o-bo ne pa hogen esponsible o Wes Nile e e and, in a e cases, se e e
neu oin asi e disease (WNND) wi h an es ima ed 10% a ali y a e. This s udy aimed o assess WNV exposu e among
esiden s o Gezi a S a e, Sudan, om 2019 o 2022. Blood samples we e collec ed om 400 pa icipan s and es ed o
WNV-speci ic IgG and IgM an ibodies using ELISA. The esul s showed ha 62.3% (249/400) we e posi i e o WNV-
IgG an ibodies, indica ing p e ious exposu e, whe eas no pa icipan s es ed posi i e o WNV-IgM, sugges ing no
ecen ac i e in ec ions. S a is ical analysis e ealed no signi ican associa ion be ween WNV-IgG se oposi i i y and age
o gende , bu signi ican co ela ions we e obse ed wi h ma i al s a us and educa ion le el. These indings highligh
he subs an ial le el o pas WNV exposu e in Gezi a S a e and unde sco e he need o ongoing su eillance, mosqui o
con ol measu es, and communi y educa ion o mi iga e po en ial ou b eaks.
Keywo ds: Wes Nile Vi us; Se op e alence; ELISA; Sudan; Vec o -Bo ne Diseases
1. In oduc ion
Wes Nile i us (WNV) is a mosqui o-bo ne la i i us ha ypically causes mild o asymp oma ic in ec ions, bu can
occasionally lead o se e e neu ological disease, wi h a case a ali y a e o app oxima ely 10% (Pe e sen e al., 2013).
Fi s iden i ied in Uganda in 1937, WNV sp ead o No h Ame ica in 1999 and has since been epo ed ac oss Eu ope,
A ica, Asia, Aus alia, and No h Ame ica (CDC, 2017; WHO, 2011). In he U.S., housands o cases a e epo ed annually,
peaking in la e summe and ea ly au umn, some imes causing ou b eaks (CDC, 2017; WHO, 2011). In Sudan, a no able
ou b eak occu ed in Ngo ban Coun y, Sou h Ko do an, be ween May and Augus 2002.
WNV is p ima ily ansmi ed h ough he bi e o in ec ed mosqui oes ha eed on in ec ed bi ds. Ra e human- o-human
ansmission can occu h ough blood ans usions, o gan ansplan s, o e ical ansmission om mo he o child
du ing p egnancy, bi h, o b eas eeding (CDC, 2017). Di ec pe son- o-pe son ansmission does no occu (WHO,
2011).
All age g oups a e suscep ible o WNV, hough indi iduals o e 60 yea s old and hose wi h unde lying heal h condi ions
ace a highe isk o se e e neu ological complica ions (Campbell e al., 2002; Solomon e al., 2003). Disease se e i y is
in luenced by i al i ulence, popula ion immuni y, and hos ac o s (Hubálek, 2001; Pe e sen and Ma in, 2002).
Diagnosis elies on clinical assessmen suppo ed by se ological and molecula es ing (CDC, 2017).
P e ious s udies in Sudan indica e ongoing WNV ac i i y. Fo ins ance, 44.4% o blood dono s in Kha oum es ed
posi i e o WNV-IgG in 2016, while 2.2% had IgM an ibodies, sugges ing ecen in ec ion (Yasi e al., 2022). This s udy
aims o e alua e WNV exposu e in Gezi a S a e and examine associa ions wi h demog aphic ac o s such as age, gende ,
ma i al s a us, and educa ion le el. Findings may imp o e diagnos ic accu acy and in o m public heal h in e en ions.
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
273
2. Ma e ials and Me hods
2.1. S udy Design and Popula ion
This c oss-sec ional, labo a o y-based s udy was conduc ed in eigh locali ies o Gezi a S a e, Sudan, om Feb ua y o
Decembe 2022. Bo h symp oma ic and asymp oma ic indi iduals we e included based on p ede ined inclusion and
exclusion c i e ia.
2.2. Sample Collec ion and P ocessing
Venous blood (5 mL) was collec ed asep ically om each pa icipan . Two mL we e placed in EDTA ubes o plasma
sepa a ion, and h ee mL we e collec ed in plain ubes o se um. Plasma was ob ained by cen i uga ion a 3000 pm
o 5 minu es, while se um was sepa a ed a e allowing he blood o clo o 10 minu es ollowed by cen i uga ion.
Samples we e s o ed a –20°C un il analysis.
2.3. Sample Size De e mina ion
Using s anda d epidemiological o mulas o achie e high con idence and minimal e o , 384 pa icipan s pe locali y
we e a ge ed o ensu e ep esen a i e esul s.
2.4. Da a Collec ion and Analysis
S uc u ed ques ionnai es we e used o collec demog aphic da a, clinical symp oms, and po en ial isk ac o s. Da a
we e analyzed using SPSS Ve sion 22, wi h signi icance se a a 95% con idence in e al.
2.5. E hical Conside a ions
E hical app o al was ob ained om he Facul y o Medical Labo a o y Sciences, Uni e si y o Gezi a, and he Gezi a
S a e Minis y o Heal h. W i en in o med consen was ob ained om all pa icipan s, and con iden iali y was
main ained.
2.6. Se ological Tes ing (ELISA)
WNV-speci ic IgM and IgG an ibodies we e de ec ed using a semi-quan i a i e ELISA ki (EUROIMMUN). The assay
in ol ed wo s eps
• An igen Binding: Samples incuba ed in WNV an igen-coa ed wells o med an igen-an ibody complexes i
an ibodies we e p esen .
• De ec ion: An enzyme-labeled an i-human IgM/IgG conjuga e p oduced a colo ime ic signal measu ed as
op ical densi y (OD).
Resul s we e exp essed as a a io o sample OD o calib a o OD
• Nega i e: <0.8
• Bo de line: 0.8–1.1
• Posi i e: ≥1.1
3. Resul s
3.1. WNV An ibody P e alence
Among 400 pa icipan s, 62.3% we e WNV-IgG posi i e, indica ing p io exposu e, while 37.7% we e nega i e. WNV-
IgM an ibodies we e absen in 97% o pa icipan s, wi h only 3% showing bo de line esul s (Table 1, Figu e 1).
3.2. Pa icipan Demog aphics
• Age: 1–19 yea s (34%), 20–39 yea s (47.3%), 40–59 yea s (16%), 60–80 yea s (2.8%)
• Gende : 62% male, 38% emale
• Ma i al s a us: 54% single, 46% ma ied
• Educa ion: 48% illi e a e, 36% high school, 11% uni e si y, 5% p ima y school
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
274
3.3. Demog aphic Associa ions wi h WNV Se oposi i i y
• IgG An ibodies: No signi ican associa ion wi h age (P = 0.060) o gende (P = 0.117). Signi ican associa ions
we e ound wi h educa ion le el (P < 0.001) and ma i al s a us (P < 0.001). Illi e a e pa icipan s had highe
nega i e IgG a es, while uni e si y g adua es showed highe posi i i y. Single pa icipan s had highe IgG
posi i i y han ma ied pa icipan s.
• IgM An ibodies: No signi ican associa ions we e obse ed wi h any demog aphic ac o s.
4. Discussion
This s udy demons a es high WNV-IgG se op e alence (62.3%) among Gezi a S a e esiden s, sugges ing widesp ead
pas exposu e. The absence o IgM an ibodies indica es minimal ecen ansmission du ing he s udy pe iod, consis en
wi h RT-PCR esul s showing no ac i e in ec ions.
Age dis ibu ion e ealed he highes IgG posi i i y among 20–39-yea -olds (43.4%), ollowed by 1–19-yea -olds (39%).
These esul s align wi h p e ious epo s indica ing highe WNV incidence among young adul s and child en (Yasi e
al., 2022; WHO, 2021).
Gende did no in luence se oposi i i y, whe eas educa ion and ma i al s a us we e signi ican ly associa ed wi h IgG
p e alence. Illi e a e indi iduals had lowe IgG posi i i y, po en ially e lec ing educed exposu e o di e ences in
heal h-seeking beha io . Compa ison wi h p io s udies indica es ou indings a e consis en wi h ecen Sudanese da a
(Yasi e al., 2022), hough sligh ly lowe han pooled es ima es o A ica (70.3%).
Figu e 1 The cha ac e is ics and pa e ns o WNV IgG and IgM an ibodies in he s udy popula ion
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
275
Figu e 2 The age dis ibu ion wi hin he s udy popula ion
Figu e 3 The dis ibu ion o gende s in he s udy popula ion
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
276
Figu e 4 The ma i al s a us dis ibu ion among he s udy popula ion
Figu e 5 The educa ional a ainmen le els wi hin he s udy popula ion
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
277
Table 1 The cha ac e is ics and pa e ns o WNV IgG and IgM an ibodies in he s udy popula ion
WNV an ibodies (n=400)
F equency
Pe cen
IgG an ibodies
Nega i e
151
37.7
Posi i e
249
62.3
Bo de line
0
0.0
IgM an ibodies
Nega i e
388
97.0
Posi i e
0
0.0
Bo de line
12
3.0
Table 2 The co ela ion be ween WNV-IgG an ibodies and popula ion cha ac e is ics
Demog aphic Va iables
WNV-IgG an ibodies
Chi-Squa e
P. alue
Nega i e (n=151)
Posi i e (n=249)
n
%
N
%
Age
1-19 (n=136)
39
25.8%
97
39.0%
7.408
0.060
20-39 (n=189)
81
53.6%
108
43.4%
40-59 (n=64)
27
17.9%
37
14.9%
60-80 (n=11)
4
2.6%
7
2.8%
Gende
Male (n=248)
101
66.9%
147
59.0%
2.459
0.117
Female (n=152)
50
33.1%
102
41.0%
Educa ional le el
Illi e a e (n=193)
96
63.6%
97
39.0%
23.352
<.001**
P ima y school (n=20)
4
2.6%
16
6.4%
High school (n=143)
40
26.5%
103
41.4%
Uni e si y (n=44)
11
7.3%
33
13.3%
Ma i al s a us
Single (n=216)
61
40.4%
155
62.2%
18.69a
<.001**
Ma ied (n=184)
90
59.6%
94
37.8%
**. signi ican a he 0.01 le el
Table 3 The co ela ion be ween WNV-IgM an ibodies and popula ion cha ac e is ics
Demog aphic Va iables
WNV-IgM an ibodies
Chi-
Squa e
P. alue
Nega i e (n=388)
Bo de line (n=12)
n
%
N
%
Age
1-19 (n=136)
132
34.0%
4
33.3%
1.118
0.773
20-39 (n=189)
182
46.9%
7
58.3%
40-59 (n=64)
63
16.2%
1
8.3%
60-80 (n=11)
11
2.8%
0
0.0%
Gende
Male (n=248)
242
62.4%
6
50.0%
0.756
0.385
Female (n=152)
146
37.6%
6
50.0%
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 272-279
278
Educa ional
le el
Illi e a e (n=193)
188
48.5%
5
41.7%
1.512
0.679
P ima y school
(n=20)
20
5.2%
0
0.0%
High school (n=143)
137
35.3%
6
50.0%
Uni e si y (n=44)
43
11.1%
1
8.3%
Ma i al
s a us
Single (n=216)
211
54.4%
5
41.7%
0.758
0.384
Ma ied (n=184)
177
45.6%
7
58.3%
5. Conclusion
The s udy e eals subs an ial pas exposu e o WNV among Gezi a S a e esiden s. Despi e widesp ead se oposi i i y,
ecen ac i e in ec ions we e no de ec ed. These indings emphasize he need o enhanced WNV su eillance, ec o
con ol, and public heal h educa ion o educe he isk o u u e ou b eaks.
Compliance wi h e hical s anda ds
Disclosu e o con lic o in e es
No con lic o in e es o be disclosed.
S a emen o e hical app o al
E hical app o al a ached.
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