Co esponding au ho : Sa ah Esadig Elagib El ahie
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Wes Nile Vi us Exposu e in Gezi a S a e, Sudan: An ELISA-Based S udy
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), 280-286
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.2025.33.1.0407
Abs ac
Wes Nile Vi us (WNV) is a mosqui o-bo ne la i i us esponsible o Wes Nile e e . Al hough mos in ec ions a e
asymp oma ic o mild, ewe han 1% p og ess o Wes Nile neu oin asi e disease (WNND), which has an es ima ed
a ali y a e o 10% (Pe e sen e al., 2013).
This c oss-sec ional s udy assessed WNV exposu e among 400 esiden s o Gezi a S a e, Sudan (2019–2022). Blood
samples we e collec ed and analyzed o WNV-speci ic IgG and IgM an ibodies using ELISA, while RT-PCR was
pe o med on IgG-posi i e samples o de ec ac i e i al RNA.
O e all, 62.3% (249/400) o pa icipan s we e posi i e o WNV-IgG an ibodies, indica ing pas exposu e, whe eas all
samples we e nega i e o WNV-IgM an ibodies, sugges ing he absence o ecen in ec ion. No signi ican co ela ions
we e obse ed be ween common isk ac o s and IgG posi i i y (P > 0.05), excep o neck s i ness, which showed a
signi ican associa ion (P < 0.05).
The high p e alence o WNV-IgG an ibodies, coupled wi h he absence o IgM posi i i y, highligh s widesp ead p io
exposu e and a lack o cu en in ec ion in he popula ion. These indings unde sco e he need o sus ained su eillance
and public heal h ini ia i es ocusing on mosqui o con ol and communi y awa eness o p e en u u e WNV ou b eaks.
Keywo ds: Wes Nile Vi us; Igg Se op e alence; Sudan; ELISA; Vec o -Bo ne Disease
1. In oduc ion
Wes Nile Vi us (WNV) is a globally dis ibu ed mosqui o-bo ne la i i us ha p ima ily causes asymp oma ic o mild
in ec ions, collec i ely e med Wes Nile e e (WNF). Se e e neu ological complica ions, including meningi is and
encephali is, occu in less han 1% o cases and a e associa ed wi h a mo ali y a e o app oxima ely 10% (Pe e sen e
al., 2013).
The i us was i s isola ed in Uganda in 1937 (Smi h bu n e al., 1940) and la e sp ead o No h Ame ica in 1999 (CDC,
2017; WHO, 2011). Since hen, ou b eaks ha e been epo ed ac oss Eu ope, A ica, Asia, Aus alia, and he Ame icas.
In he Uni ed S a es, seasonal ou b eaks ypically peak in la e summe (CDC, 2017). App oxima ely 80% o WNV
in ec ions a e asymp oma ic, 20% esul in WNF, and ewe han 1% de elop neu oin asi e disease cha ac e ized by
neck s i ness, con usion, o seizu es (Campbell e al., 2002; CDC, 2017).
T ansmission occu s mainly h ough bi es om in ec ed Culex mosqui oes, which acqui e WNV a e eeding on i emic
bi ds. Ra e ansmission ou es include blood ans usion, o gan ansplan a ion, and e ical ansmission om
mo he o child (WHO, 2011; CDC, 2019). Elde ly indi iduals and hose wi h como bidi ies a e a g ea e isk o se e e
ou comes.
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 280-286
281
His o ically, ea ly epidemics we e cha ac e ized by eb ile illness wi h ash and lymphadenopa hy (Ma be g e al., 1956;
Hayes, 1989), while mo e ecen ou b eaks in Romania (1996), Russia (1999), he Uni ed S a es (1999), and Is ael
(2000) ha e been domina ed by neu ological symp oms (Tsai e al., 1998; Pla ono e al., 2001; Chowe s e al., 2001).
Culex mosqui oes a e abundan in Sudan, pa icula ly in Gezi a S a e, sugges ing a po en ially high WNV ansmission
isk. Howe e , limi ed epidemiological da a exis , as mos p e ious s udies ha e ocused on speci ic popula ions such as
blood dono s (Ahmed e al., 2011). This s udy aimed o de e mine he se op e alence o WNV an ibodies and associa ed
isk ac o s among esiden s o Gezi a S a e using ELISA-based de ec ion o IgM and IgG.
2. Ma e ials and Me hods
2.1. S udy Design and Popula ion
A c oss-sec ional, labo a o y-based s udy was conduc ed in Gezi a S a e, Sudan, be ween Feb ua y and Decembe 2022.
Bo h symp oma ic and asymp oma ic indi iduals we e ec ui ed acco ding o p ede ined inclusion and exclusion
c i e ia.
2.2. Sample Collec ion and P ocessing
Fi e millili e s o enous blood we e collec ed asep ically om each pa icipan —2 mL in EDTA ubes ( o plasma) and
3 mL in plain ubes ( o se um). Plasma was sepa a ed immedia ely, while se um was ob ained a e clo ing by
cen i uga ion a 3000 pm o 5 minu es. Samples we e s o ed a −20°C un il analysis.
2.3. Sample Size
A o al o 400 pa icipan s we e en olled, exceeding he minimum calcula ed sample size o 384 o ensu e
ep esen a i eness.
2.4. Se ological Tes ing
WNV-speci ic IgM and IgG an ibodies we e de ec ed using EUROIMMUN ELISA ki s ollowing manu ac u e ins uc ions.
Samples wi h a a io ≥1.1 we e conside ed posi i e, 0.8–1.1 bo de line, and <0.8 nega i e.
2.5. Da a Collec ion and S a is ical Analysis
Demog aphic and clinical da a we e collec ed using s uc u ed ques ionnai es. S a is ical analysis was pe o med wi h
SPSS ( e sion 22) using chi-squa e and logis ic eg ession es s. A p- alue <0.05 was conside ed s a is ically signi ican .
2.6. 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. In o med consen was ob ained om all pa icipan s, and con iden iali y was main ained
h oughou he s udy.
3. Resul s
3.1. Se op e alence o WNV
Among 400 pa icipan s, 62.3% (249) es ed posi i e o WNV-IgG, while 37.8% (151) we e nega i e. All samples we e
nega i e o WNV-IgM, al hough 12 yielded bo de line esul s.
3.2. Symp oma ology
Commonly epo ed symp oms included headache (16.3%), lu-like symp oms (13.8%), and e e (13.5%). Less
equen symp oms we e omi ing (6.8%), ash (5.5%), and neck s i ness (2.5%).
3.3. Medical His o y
Mos pa icipan s (95.3%) epo ed no ch onic diseases, and 98.8% had no his o y o blood ans usion o o gan
ansplan a ion.
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 280-286
282
3.4. Associa ion Analyses
No signi ican associa ions we e ound be ween WNV-IgG posi i i y and mos symp oms (P > 0.05), excep o neck
s i ness (P = 0.005). Logis ic eg ession e ealed signi ican associa ions be ween IgG posi i i y and gende ( emale,
OR = 1.82), educa ional le el (OR = 1.42), ma i al s a us (OR = 0.33), and neck s i ness (OR = 0.08).
4. Discussion
The high WNV-IgG se op e alence (62.3%) obse ed in Gezi a S a e indica es widesp ead pas exposu e, consis en
wi h p e ious Sudanese s udies epo ing a es be ween 60% and 75% (Ahmed e al., 2011; Mohammed e al., 2019).
The absence o IgM posi i i y con i ms he lack o ongoing ansmission du ing he s udy pe iod.
No signi ican associa ions we e de ec ed be ween IgG posi i i y and mos symp oms, which suppo s he ypically
asymp oma ic cou se o WNV in ec ion (Campbell e al., 2002). The obse ed co ela ion wi h neck s i ness aligns wi h
epo s linking neu oin asi e mani es a ions o p io exposu e (Sej a e al., 2003).
En i onmen al and ecological ac o s, including mosqui o abundance and clima ic condi ions, likely play a majo ole in
sus aining WNV ci cula ion in Gezi a S a e. Limi ed labo a o y capaci y and low public awa eness u he hinde ea ly
de ec ion and con ol. S eng hening su eillance and inco po a ing WNV sc eening in o blood dona ion p og ams a e
he e o e c i ical (WHO, 2011; CDC, 2019).
Figu e 1 Symp oms dis ibu ion o he s udy popula ion
Figu e 2 The medical backg ound o he s udy popula ion
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 280-286
283
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 dis ibu ion o symp oms among he s udy popula ion
Symp oms (n=400)
No
Yes
F equency
Pe cen
F equency
Pe cen
Fe e
346
86.5
54
13.5
Vomi ing
373
93.3
27
6.8
Rash
378
94.5
22
5.5
Headache
335
83.8
65
16.3
Neck s i ness
390
97.5
10
2.5
Flue like
345
86.3
55
13.8
Table 3 The medical backg ound o he s udy popula ion
Medical His o y (n=400)
No
Yes
F equency
Pe cen
F equency
Pe cen
Ch onic disease
381
95.3
19
4.8
Blood ans usion
395
98.8
5
1.3
O gan ansplan a ion
400
100.0
0
0.0
Table 4 Co ela ion be ween WNV-IgG an ibodies and clinical symp oms
WNV-IgG an ibodies
Chi-Squa e
P. alue
Nega i e (n=151)
Posi i e (n=249)
n
%
N
%
Fe e
No (n=346)
136
90.1%
210
84.3%
2.642
0.104
Yes (n=54)
15
9.9%
39
15.7%
Vomi ing
No (n=373)
139
92.1%
234
94.0%
0.552
0.457
Yes (n=27)
12
7.9%
15
6.0%
Rash
No (n=378)
146
96.7%
232
93.2%
2.236
0.135
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 280-286
284
Yes (n=22)
5
3.3%
17
6.8%
Headache
No (n=335)
128
84.8%
207
83.1%
0.185
0.667
Yes (n=65)
23
15.2%
42
16.9%
Neck s i ness
No (n=390)
143
94.7%
247
99.2%
7.791
0.005*
Yes (n=10)
8
5.3%
2
0.8%
Flue like
No (n=345)
134
88.7%
211
84.7%
1.270
0.260
Yes (n=55)
17
11.3%
38
15.3%
*. signi ican a he 0.05 le el
Table 5 Co ela ion be ween WNV-IgM an ibodies and clinical symp oms
WNV-IgM an ibodies
Chi-Squa e
P. alue
Nega i e (n=388)
Bo de line (n=12)
n
%
n
%
Fe e
No (n=346)
335
86.3%
11
91.7%
0.283
0.595
Yes (n=54)
53
13.7%
1
8.3%
Vomi ing
No (n=373)
361
93.0%
12
100.0%
0.895
0.344
Yes (n=27)
27
7.0%
0
0.0%
Rash
No (n=378)
367
94.6%
11
91.7%
0.191
0.662
Yes (n=22)
21
5.4%
1
8.3%
Headache
No (n=335)
323
83.2%
12
100.0%
2.400
0.121
Yes (n=65)
65
16.8%
0
0.0%
Neck s i ness
No (n=390)
378
97.4%
12
100.0%
0.317
0.573
Yes (n=10)
10
2.6%
0
0.0%
Flue like
No (n=345)
334
86.1%
11
91.7%
0.306
0.580
Yes (n=55)
54
13.9%
1
8.3%
Table 6 Co ela ion be ween WNV-IgG an ibodies and medical his o y
WNV-IgG an ibodies
Chi-Squa e
P. alue
Nega i e (n=151)
Posi i e (n=249)
n
%
n
%
Ch onic disease
No (n=381)
143
94.7%
238
95.6%
0.161
0.688
Yes (n=19)
8
5.3%
11
4.4%
Blood ans usion
No (n=395)
151
100.0%
244
98.0%
3.071
0.080
Yes (n=5)
0
0.0%
5
2.0%
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 280-286
285
Table 7 Co ela ion be ween WNV-IgM an ibodies and medical his o y
WNV-IgM an ibodies
Chi-Squa e
P. alue
Nega i e (n=388)
Bo de line (n=12)
n
%
n
%
Ch onic disease
No (n=381)
369
95.1%
12
100.0%
0.617
0.432
Yes (n=19)
19
4.9%
0
0.0%
Blood ans usion
No (n=395)
383
98.7%
12
100.0%
0.157
0.692
Yes (n= 5)
5
1.3%
0
0.0%
Table 8 Logis ic eg ession analysis o ac o s associa ed wi h WNV-IgG se oposi i i y
Fac o s
P. alue
Odds a io
95% con idence in e al
Lowe
Uppe
Fe e
0.278
1.527
0.711
3.283
Vomi ing
0.140
0.499
0.198
1.256
Rash
0.628
1.355
0.397
4.632
Headache
0.846
1.071
0.534
2.151
Neck s i ness
0.006*
0.082
0.014
0.486
Flue like
0.314
1.466
0.696
3.087
Ch onic disease
0.365
1.818
0.499
6.630
Blood ans usion
0.999
0.000
0.000
.
*. signi ican a he 0.05 le el
Table 9 Logis ic eg ession analysis o ac o s associa ed wi h WNV-IgM se oposi i i y
Fac o s
P. alue
Odds a io
95% con idence in e al
Lowe
Uppe
Fe e
0.806
0.731
0.060
8.841
Vomi ing
0.998
0.000
0.000
.
Rash
0.295
4.088
0.293
56.939
Headache
0.997
0.000
0.000
.
Neck s i ness
0.999
0.000
0.000
.
Flue like
0.960
0.939
0.084
10.498
Ch onic disease
0.998
0.000
0.000
.
Blood ans usion
0.999
0.000
0.000
.
5. Conclusion
This s udy demons a es a high p e alence o WNV-IgG an ibodies among esiden s o Gezi a S a e, e lec ing ex ensi e
pas exposu e bu no cu en in ec ion. These indings highligh he u gen need o enhanced ec o su eillance,
mosqui o con ol p og ams, and in eg a ion o WNV diagnos ics in o na ional heal h s a egies. Inc easing public and
heal hca e awa eness is i al o educe misdiagnosis and mo bidi y associa ed wi h WNV in Sudan.
GSC Biological and Pha maceu ical Sciences, 2025, 33(01), 280-286
286
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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