B. Orindi

E. Chepkorir

F. Mulwa

J. Lutomiah

J. Mutisya

R. Sang

Z. Ng’ang’a

International Journal of Infectious Diseases

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The vector competence of Ae. aegypti mosquito populations from Kilifi and Nairobi for dengue-2 virus and the effect of temperature

Chepkorir, E.

Lutomiah, J.

Mutisya, J.

Mulwa, F.

Orindi, B.

Ng’ang’a, Z.

Sang, R.

Elsevier - Publisher Connector 

16th ICID Abstracts / International Journal of Infectious Diseases 21S (2014) 1–460 3
Despite the widespread distribution of ZIKV, the genetic relation-
ships among the circulating viral strains remain poorly understood.
Therefore, we undertook a study on phylogeny and phylodynamics
ZIKV in Africa and Asia.
Methods & Materials: We investigated 37 ZIKV isolates from
1968 to 2002 obtained from Senegal, Ivory Coast, Burkina Faso,
Central African Republic and Malaysia, to evaluate the viral spread
and its molecular epidemiology. Phylogenetic reconstructions and
datation were performed while recombination while viral popula-
tion migrations were investigated.
Results: Phylogenetic analysis of the 3 partial gene (E, NS5 and
NS5/3’NC) showed two distinct ZIKV clusters circulate in Africa
and a third lineage formed by the Micronesia and Malaysia strains.
Besides, analysis of full length genome sequence reveal 5 potential
recombinants isolates in Senegal and Ivory Cost. The 3 gene regions
sequences evolved at a average rate of 7.74 x 10-4 nucleotide
substitutions per site per year with a most recent common ances-
tor of all ZIKV samples around 325 years ago. The migration rates
showeda considerablemovementof thevirus fromSenegal to Ivory
Cost and the other countries include in this study.
Conclusion: Our results suggested at least two independent
introductions of ZIKV during the 20th century in West Africa and,
apparently that viral lineages were not restricted by mosquito
vector species. Moreover, we present evidence that ZIKV possibly
undergone recombination in nature and that a loss of the N154 gly-
cosylation site in the envelope was a possible adaptive response to
the Aedes dalzieli vector.
http://dx.doi.org/10.1016/j.ijid.2014.03.411
Type: Oral Presentation
Final Abstract Number: Pre.005
Session: Pre-Congress Symposium: Emerging African Investigators
Symposium
Date: Wednesday, April 2, 2014
Time: 13:00-17:00
Room: Room Roof Terrace
Dengue fever outbreak in Mogadishu, Somalia
2011: Co-circulation of three dengue virus
serotypes
H. Kyobe Bosa1,∗, J.M. Montgomery2, I. Kimuli3,
J.J. Lutwama4
1 AMISOM, Mogadishu, Somalia
2 Centers for Disease Control and Prevention-Kenya
(CDC-K), Nairobi, Kenya
3 Makerere University, Kampala, Uganda
4 Uganda Virus Research Institute, Entebbe, Uganda
Background: In June 2011 an acute febrile illness (AFI) out-
break, with three deaths, was reported among African Union
Mission in Somalia (AMISOM)peacekeepers inMogadishu. Allwere
negative for malaria by blood smear. An initial set of samples
(n =122) were sent to CDC-Kenya/Kenyan Medical Research Insti-
tute (CDC/KEMRI) laboratories to test for various viral hemorrhagic
fevers by RT-PCR. A majority (82%) were positive for dengue virus
(DENV).
Methods & Materials: CDC-Kenya and CDC-Uganda subse-
quently supported AMISOM to implement an enhanced hospital-
based dengue fever surveillance system in two military hospitals
in Mogadishu. Case deﬁantion: all patients with axillary tempera-
ture >380C
Results: During June—August 2011,134 (94%) of 143 blood sam-
ples fromAFI caseswere testedbyRT-PCRandMAC-ELISA.Of these,
62% were positive for DENV by RT-PCR, 18% (n=24) had a pos-
itive sole anti-DENV MAC-ELISA and 20% had a negative RT-PCR
and MAC-ELISA. All specimens had negative malaria smear or RDT.
Infections of DENV-1, DENV-2, DENV-3 and co-infections of DENV-
1/2 andDENV-2/3 sero-typeswere identiﬁed in37%, 7%, 25%, 1%and
25%, respectively. Of the conﬁrmed cases (n =107; 75%), median
age was 32 years (range 20-49), majority (96%) were male and 60%
were hospitalized (median length of stay =3.5 days). Of the hospi-
talized patients, 87% had leucopenia (WBC<3.5x103 cells) and 83%
thrombocytopenic (platelet count <100x103 cells).
Except for a high proportion of hemorrhagic manifestations
(n =14, 13%), frequency of other clinical ﬁndings (fever, headache,
joint pains, vomiting andbodypains) (≥60%)was consistent aswith
other settings.
Conclusion: Co-circulation of multiple dengue sero-types and
possible repeated secondary heterotypic dengue infections may be
responsible for a high proportion of severe forms of dengue, includ-
ing death. The extent of severe dengue infection, co-circulation
of three dengue serotypes and co-infection with multiple dengue
sero-types has not been previously documented in African. Despite
the limited scope of this study given the hospital-based design
it appears the intensity of dengue fever transmission, severity of
dengue in this setting appears under-reported especially in the
civilian population.
Given the frequent rotations of peacekeepers from Somalia, the
potential of dengue viruses’ importation to many African countries
where the vectors exist is real.
http://dx.doi.org/10.1016/j.ijid.2014.03.412
Type: Poster Presentation
Final Abstract Number: Pre.006
Session: Pre-Congress Symposium: Emerging African Investigators
Symposium
Date: Wednesday, April 2, 2014
Time: 13:00-17:00
Room: Room Roof Terrace
The vector competence of Ae. aegypti mosquito
populations from Kiliﬁ and Nairobi for
dengue-2 virus and the effect of temperature
E. Chepkorir1,∗, J. Lutomiah2, J. Mutisya3, F.
Mulwa1, B. Orindi1, Z. Ng’ang’a4, R. Sang1
1 International Center for Insect Physiology and
Ecology (ICIPE), Nairobi, Kenya
2 Kenya Medical Research Institute (KEMRI), Nairobi,
Kenya
3 United States Army Medical Research Unit-Kenya
(USAMRU-K), Nairobi, Kenya
4 Jomo Kenyatta University of Agriculture and
Technology, Nairobi, Kenya
Background: Dengue virus principally transmitted by Aedes
aegypti mosquitoes, is a re-emerging infection in Kenya causing
major outbreaks in parts of Northern Kenya since 2011 and Coastal
regions in 2013. Since these outbreaks started, no cases have been
reported in Nairobi despite the level of human movement among
these cities. In addition to the vector population/strains, tempera-
ture is one of the most important environmental factor affecting
biological processes of mosquitoes, including their interactions
with viruses.
4 16th ICID Abstracts / International Journal of Infectious Diseases 21S (2014) 1–460
Methods & Materials: Ae. aegypti eggs were collected from
the two sites, hatched and reared to F1 generation in a Biosafety
level-2 insectary. Four-day old females were exposed to infectious,
deﬁbrinated sheep-blood mixed (1:1 ratio) with Dengue-2 virus
isolated fromMandera-(5.08pfu/ml), using amembrane feeder. Fed
mosquitoes were incubated under two sets of temperatures equiv-
alent to thecoastal-(29-31 ◦C)andNairobi-(25-28 ◦C) regionannual
mean temperatures. In both experiments mosquitoes were moni-
tored for up to 21days, and at 7day intervals, a thirdwere randomly
sampled, legs and abdomen separated. Abdomens were homoge-
nized and virus quantiﬁed by plaque assay to determine midgut
infection rates. Legs for mosquitoes with midgut infection were
assayed for virus to determine dissemination rates. Results were
compared using Chi-square/Fisher’s exact test.
Results: A total of 1,117 female Ae.aegypti mosquitoes were
tested. 87/517(16.8%; 95%CI: 13.7-20.3%) of Nairobi mosquitoes
had infection. The proportion infected was signiﬁcantly greater
in high temperature (21.3%) than low temperature (12.0%;
p=0.0037). For Kiliﬁ mosquitoes 54/600 (9%; 95%CI: 6.8-11.6%)
were infected, this proportion also varied signiﬁcantly with tem-
perature (high=11.6%, low=6.8%; p=0.0162). Among the infected
mosquitoes, the proportion that had dissemination was signif-
icantly greater in Kiliﬁ (40.7%; 95%CI: 27.6-55.0%) than Nairobi
(10.3%; 95%CI: 4.8-18.7%; p<0.0001).
Conclusion: There is signiﬁcant difference in midgut infection
rates under varying temperatures for both populations from the
two geographical sites. Although it was observed that dissemina-
tion rates did not vary signiﬁcantly with temperature in the two
populations, the Kiliﬁ population exhibited a high dissemination
rates compared to the Nairobi population suggesting that the Kiliﬁ
populationmaybe inherentlymore competentwitha lowermidgut
barrier than the Nairobi population. These ﬁnding are important in
understanding the distribution of re-emerging Infectious diseases
in Africa.
http://dx.doi.org/10.1016/j.ijid.2014.03.413
Type: Oral Presentation
Final Abstract Number: Pre.007
Session: Pre-Congress Symposium: Emerging African Investigators
Symposium
Date: Wednesday, April 2, 2014
Time: 13:00-17:00
Room: Room Roof Terrace
Bacteriuria and urinary schistosomiasis in
primary school children in rural communities
in Enugu State, Nigeria, 2012
O. Ossai1,∗, S.A. Idris2, G. Abonyi3, D. Turkur2, R.
Dankoli 4, O. Ekwueme5, D. Nwagbo5, E.
Ezeanolue6, O. Nwanyanwu7, C.C. Nwodo8, P.
Nguku9, P. Nsubuga10, D. Ogbuabor5
1 Nigerian Field Epidemiology and Laboratory
Training Programme(NFELTP), Abuja, Abuja, Nigeria
2 Ahmadu Bello University, Zaria, Nigeria
3 Enugu State Ministry of Health, Enugu, Nigeria
4 NFELTP, Abuja, Nigeria
5 University of Nigeria, Enugu, Nigeria
6 Las Vegas University, las Vegas, USA
7 CDC, Nigeria, Abuja, Nigeria
8 Nigerian Field Epidemiology and Laboratory
Training Programme(NFELTP), Abuja, Nigeria
9 FELTP, Abuja, FCT, Nigeria
10 US Centers for Disease Control and Prevention,
Atlanta, GA, USA
Background: According to a study conducted in1989, Enugu
State has an estimated urinary schistosomiasis prevalence of 79%.
Recently, studies have implicated bacteriuria co-infection in blad-
der cancer. These bacteria accelerate the multi-stage process of
bladder carcinogenesis. Knowledge about the prevalence of this co-
infection is not available in Enugu and the information provided by
the 1989 study is too old to be used for current decision making.
Methods & Materials: We carried out a cross-sectional sur-
vey of primary school children aged5-15years, whowere randomly
selected through a multi stage sampling method using guidelines
recommendedbyWHO for schistosomiasis surveys. An interviewer
administered questionnaire was used to collect data on demog-
raphy, socioeconomic variables and clinical presentations. Urine
sampleswere collectedbetween10.00amand2.00pm.Each sample
wasdivided into two: (A) for prevalence and intensity using syringe
ﬁltration technique and (B) for culture. Intensitywas categorized as
heavy (>50ova/10mlsurine) and light (<50ova/10mlsurine). Signif-
icant bacteriuria was bacteria count ≥ 105 colony forming units/ml
of urine.
Results Of the 842 pupils, 50.6% were females. The preva-
lence of urinary schistosomiasis was 34.1%. Infection rate was
higher(52.8%) among13-15years(PrevalenceRatio {PR}=2.45, 95%
Conﬁdence Interval{CI} 1.63-3.69).Heavy infectionswad 62.7% and
egg count/10mls urine ranged from21-1138.Signiﬁcant bacteriuria
among pupils with urinary schistosomiasis was 53.7% compared
to 3.6% in the uninfected(PR=30.8,95% CI 18.91-52.09). The com-
monest implicated organism was Escherchia.coli.
Conclusion We found high prevalence of bacteriuria co-
infection among children with urinary schistosomiasis in Enugu
State. This underscores the need for concurrent antibiotics admin-
istration and follow-up to avert later complications.
http://dx.doi.org/10.1016/j.ijid.2014.03.414


The vector competence of Ae. aegypti mosquito populations from Kilifi and Nairobi for dengue-2 virus and the effect of temperature 

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The vector competence of Ae. aegypti mosquito populations from Kilifi and Nairobi for dengue-2 virus and the effect of temperature

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