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R E S E A R C H A R T I C L E Open Access
Malaria prevalence, anemia and baseline
intervention coverage prior to mass net
distributions in Abia and Plateau States, Nigeria
Gregory S Noland
1*
, Patricia M Graves
1,9
, Adamu Sallau
2
, Abel Eigege
2
, Emmanuel Emukah
3
, Amy E Patterson
1,10
,
Joseph Ajiji
4
, Iheanyichi Okorofor
5
, Oji Uka Oji
5
, Mary Umar
4
, Kal Alphonsus
2
, James Damen
6
, Jeremiah Ngondi
1
,
Masayo Ozaki
1
, Elizabeth Cromwell
1
, Josephine Obiezu
3
, Solomon Eneiramo
2
, Chinyere Okoro
7
,
Renn McClintic-Doyle
1
, Olusola Oresanya
8
, Emmanuel Miri
2
, Paul M Emerson
1
and Frank O Richards Jr
1
Abstract
Background: Nigeria suffers the world’s largest malaria burden, with approximately 51 million cases and 207,000
deaths annually. As part of the country’s aim to reduce by 50% malaria-related morbidity and mortality by 2013, it
embarked on mass distribution of free long-lasting insecticidal nets (LLINs).
Methods: Prior to net distribution campaigns in Abia and Plateau States, Nigeria, a modified malaria indicator
survey was conducted in September 2010 to determine baseline state-level estimates of Plasmodium prevalence,
childhood anemia, indoor residual spraying (IRS) coverage and bednet ownership and utilization.
Results: Overall age-adjusted prevalence of Plasmodium infection by microscopy was similar between Abia (36.1%,
95% CI: 32.3%–40.1%; n = 2,936) and Plateau (36.6%, 95% CI: 31.3%–42.3%; n = 4,209), with prevalence highest
among children 5-9 years. P. malariae accounted for 32.0% of infections in Abia, but only 1.4% of infections in
Plateau. More than half of children ≤10 years were anemic, with anemia significantly higher in Abia (76.9%, 95% CI:
72.1%–81.0%) versus Plateau (57.1%, 95% CI: 50.6%–63.4%). Less than 1% of households in Abia (n = 1,305) or
Plateau (n = 1,335) received IRS in the 12 months prior to survey. Household ownership of at least one bednet of
any type was 10.1% (95% CI: 7.5%–13.4%) in Abia and 35.1% (95% CI: 29.2%-41.5%) in Plateau. Ownership of two or
more bednets was 2.1% (95% CI: 1.2%–3.7%) in Abia and 14.5% (95% CI: 10.2%–20.3%) in Plateau. Overall reported
net use the night before the survey among all individuals, children <5 years, and pregnant women was 3.4%, 6.0%
and 5.7%, respectively in Abia and 14.7%, 19.1% and 21.0%, respectively in Plateau. Among households owning nets,
34.4% of children <5 years and 31.6% of pregnant women in Abia used a net, compared to 52.6% of children and
62.7% of pregnant women in Plateau.
Conclusions: These results reveal high Plasmodium prevalence and childhood anemia in both states, low baseline
coverage of IRS and LLINs, and sub-optimal net use—especially among age groups with highest observed malaria
burden.
Keywords: Malaria, Plasmodium, Falciparum, Malariae, Anemia, Net use, Net ownership, Nigeria, LLIN, Bed net
* Correspondence: gnoland@emory.edu
1
The Carter Center, 453 Freedom Parkway, Atlanta, GA 30307, USA
Full list of author information is available at the end of the article
© 2014 Noland et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain
Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article,
unless otherwise stated.
Noland et al. BMC Infectious Diseases 2014, 14:168
http://www.biomedcentral.com/1471-2334/14/168
Background
In Nigeria, approximately 97% of the estimated 160 mil-
lion inhabitants are at risk of Plasmodium infection [1],
resulting in an estimated 51 million cases and 207,000
deaths annually—more than any other country in the
world and approximately 25% of the total malaria burden
within Africa [2]. Malaria reportedly accounts for an esti-
mated 60% of outpatient visits in Nigeria, 30% of hospitali-
zations, 30% of under-five mortalities, 25% of infant
mortalities and 11% of maternal mortalities [3]. Beyond
the impact on human health, malaria exerts a large eco-
nomic burden on individuals and households, with the
loss due to protection, treatment and indirect costs esti-
mated to consume an estimated 132 billion Naira ($835
million) [4].
In 2008, the Nigerian Ministry of Health committed to
an ambitious goal of reducing by 50% malaria-related
morbidity and mortality by 2013 [5]. This is to be achieved
through scale-up for impact (SUFI) of World Health
Organization (WHO)-recommended prevention and con-
trol measures in order to provide protection for all at-risk
Nigerians. Specific targets set by the National Malaria
Control Strategic Plan for 2009-2013 include: at least 80%
of households own two or more insecticide treated nets
(ITN) by 2010; at least 80% of pregnant women and chil-
dren under five years of age sleep under an ITN nightly by
2010; at least 8% (by 2010) and 20% (by 2013) of house-
holds in targeted areas receive indoor residual spraying
(IRS); and 100% of pregnant women attending antenatal
care clinics receive two doses of intermittent preventative
therapy (IPTp) by 2013.
Use of ITNs is considered one of the most cost-effective
interventions against malaria in highly endemic areas [6].
ITNs are associated with significant reductions in malaria
morbidity and mortality [7], reduced complications associ-
ated with malaria in pregnancy [8], and reduced all cause
mortality [7]. In 2008, 8.0% of households in Nigeria
owned at least one ITN and only 2.7% owned two or more
ITNs, while use of ITNs was 6% among children under five
years and 5% among pregnant women [3]. Beginning in
2009, the National Malaria Control Programme launched
a two-pronged strategy for distribution of long lasting
insecticidal nets (LLINs) across the country’s 36 states
and Federal Capital Territory (FCT). The first ‘catch-up’
phase aimed to rapidly scale up LLIN ownership through
mass campaigns targeting the distribution of 64 million
LLINs (2 nets for each of 32 million households). The sec-
ond ‘keep-up’phase involves the expansion of routine dis-
tribution channels in order to sustain the high-level
coverage attained through universal mass distribution.
Routine channels, which include antenatal care clinics,
immunization clinics, school-based distributions, and the
commercial sector, had been utilized under previous na-
tional strategic plans to provide nets to pregnant women
and children under five years—populations considered
most vulnerable to malaria.
Administratively, Nigeria’s 36 states are divided into six
geo-political zones (Figure 1). The national demographic
and health surveys (DHS) of 2003 [9] and 2008 [3] pro-
vided net coverage estimates at the national and geo-
political zone level, while the national malaria indicator
survey (MIS) of 2010 [1] provided national and zonal esti-
mates of malaria intervention coverage as well as parasite
prevalence in children under five years. However, surveys
designed to evaluate the scale-up of malaria interventions
and parasite prevalence amongst all age groups with state-
level precision are lacking.
The Carter Center has helped to support net distribu-
tion efforts in Nigeria since 2004. This began with inte-
grated ITN distribution during mass drug administration
(MDA) for lymphatic filariasis and onchocerciasis [10].
Since anopheline mosquitoes can transmit both Plasmo-
dium and Wuchereria bancrofti parasites, nets provide
protection and reduce transmission of both diseases
simultaneously, while enabling programmatic efficiency
and cost savings [11,12]. In order to help evaluate the
impact of mass LLIN distribution in Abia and Plateau
States, The Carter Center coordinated a modified mal-
aria indicator survey on behalf of the state ministries of
health in September 2010, prior to the states’planned
mass distribution campaigns. The goal of this survey
was to determine baseline state-level estimates of net
ownership and utilization, Plasmodium prevalence in all
age groups and anemia prevalence in children less than
11 years old in Abia and Plateau States, Nigeria.
Methods
Study area and sample selection
This study was conducted in September 2010 in Abia
State (population est. 3.2 million) located in the South
East Zone and Plateau State (population est. 3.6 million)
located in North Central Zone (Figure 1). Malaria trans-
mission in Abia is predicted to typically last ten months
or longer (March-December), while in Plateau, a shorter
seven-month seasonal transmission period predomi-
nates (May-November) [13].
A random cluster sampling design was used to select a
state-level representative sample in each state. The re-
quired sample size was based on detection of a 50% preva-
lence of malaria in children under five years with 5%
precision, α= 0.05 and a design effect of 2. Assuming a
70% response rate and that 80% of households include at
least one child less than five years of age, approximately
1400 households were required per state. Clusters were
defined as a census enumeration area (EA), or a randomly
selected segment of large EAs, with an expected average
of 25 households per cluster. Using a list of all EAs within
each state obtained from the Nigerian National Population
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Commission, 60 clusters per state were selected in system-
atic (equal interval) fashion with a random start. Survey
teams made a rough listing and sketch map of household
locations within each cluster, and if the number of house-
holds exceeded pre-defined thresholds, the cluster was
randomly divided into segments and one segment ran-
domly selected according to the Multiple Indicator Cluster
Survey (MICS) methods [14]. All households within se-
lected clusters were eligible for inclusion in the study. If
no one was home at the time of first visit, interviewers
returned later in the day in an attempt to include all eli-
gible households.
A household was defined as: a married man, his wives
and all of his dependents who currently live with him (in-
cluding biological children, adoptive children, domestic
workers, other family members for whom he is respon-
sible); an unmarried (widowed, divorced, never married)
woman who is recognized as the head of household and
Plateau
Abia
Legend
Figure 1 Study areas and Plasmodium prevalence by cluster. Plasmodium prevalence, diagnosed by microscopy, by survey cluster site in Abia and
Plateau States, Nigeria. State maps outline their constituent local government areas (LGAs), while the national map highlights the six geo-political zones
within Nigeria.
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all of her dependents who currently live with her; or two
or more unmarried adult persons who sleep in the same
dwelling unit and who share meals (e.g. university stu-
dents who share an apartment).
Survey questionnaire
The survey questionnaire was based on the Roll Back
Malaria Monitoring & Evaluation Reference Group
(MERG) Malaria Indicator Survey household and women’s
questionnaires, modified for local conditions [15]. The
questionnaires were translated and printed in Hausa and
Igbo languages, and field tested prior to the survey.
Household interviews were conducted with consenting
heads of households or another resident adult if the head
of household was absent or unable to respond. Respon-
dents were asked about demographic information of usual
residents, standard socio-economic indicators, educational
level, household construction, indoor residual spraying as
well as mosquito net ownership, utilization, condition and
care (verified by direct observation). One woman of repro-
ductive age (15–49 years) from each household was se-
lected at random to answer the women’s questionnaire,
which included questions relating to malaria knowledge,
attitudes, practice, and exposure to malaria health mes-
sages. Geo-coordinates of each household were recorded
using handheld global positioning system units (Garmin
eTrex H, Garmin International).
Blood testing
All children ten years of age or younger as well as indi-
viduals of all ages in every third household were eligible
for malaria parasite testing by rapid diagnostic test
(RDT) and microscopy. RDT testing from finger prick
samples was used for on-site diagnosis and treatment of
malaria. CareStart Malaria HRP2/pLDH combo RDTs
(Access Bio, Inc., model G0131), which can discriminate
non-P. falciparum infections from pan-Plasmodium in-
fections, were used according to the manufacturer’s in-
structions. Thick and thin blood films were prepared by
laboratory technologists on a single slide, air dried and
stained with Giemsa on the day of collection. Blood films
were read by certified laboratory scientists in The Carter
Center laboratory in Owerri, Imo State (for Abia samples)
and The Carter Center laboratory in Jos, Plateau State (for
Plateau samples). A WHO-certified microscopist then re-
read all positive slides and 10% of the negatives from both
states for quality control. Individuals with positive RDT
results were offered on-site treatment according to na-
tional guidelines: artesunate-amodiaquine (Sanofi-Aventis
Groupe) or artemether-lumefantrine (Coartem, Novartis
AG) for non-pregnant individuals older than four months
of age, or sulfadoxine-pyrimethamine for self-reported
pregnant women. Individuals younger than four months
with a positive RDT test were referred to the nearest
health facility for further evaluation, as were RDT-negative
individuals with self-reported fever or other overt signs of
clinical illness. To enable maximum participation for
blood sampling, households with absentees were revisited
later the same day to recruit individuals missing at the first
visit.
Blood samples were also used for anemia testing in all
children under 11 years of age using handheld spectro-
photometers (Hb201+, HemoCue, Inc.). Anemia was
classified according to WHO guidelines [16] using altitude-
adjusted hemoglobin (Hb) values: mild (10.0 g/dL ≤Hb
< 11.0 g/dL), moderate (7.0 g/dL ≤Hb < 10.0 g/dL), severe
(Hb <7.0 g/dL) for children less than five years; and mild
(11.0 g/dL ≤Hb < 11.5 g/dL), moderate (8.0 g/dL ≤Hb
< 11.0 g/dL), severe (Hb <8.0 g/dL) for children 5–11 years.
Individuals with moderate anemia were provided treat-
ment according to national guidelines: presumptive
anti-malarial chemotherapy (artesunate-amodiaquine or
artemether-lumefantrine), iron supplementation (iron
syrup for those between four months and five years or
iron-folate tablets for children less than five years), and
a single dose 400 mg albendazole for children less than
two years. Individuals with severe anemia were referred
directly to the nearest health facility for evaluation and
treatment.
Data analysis
Completed questionnaires were checked by supervisors in
the field and inconsistencies verified with the respondents.
Data were double entered by different clerks in each state
and compared for consistency using EpiInfo™v3.5.3 (Cen-
ters for Disease Control and Prevention). Statistical analysis
was conducted using Stata v11.2 (StataCorp LP). Point esti-
mates and confidence intervals were derived using the
SURVEY (SVY) commands in Stata to account for cluster-
ing and sampling weights. Logistic regression models under
the SVY command were used to calculate Plasmodium
prevalence estimates for each state adjusted for age, cluster-
ing and sampling weights.
A household wealth index was constructed using the
methods of Vyas and Kumaranayake [17]. This index
was based on possession of assets (having electricity in
the household, a functioning radio and/or a functioning
television), type and location of usual water source, pos-
session of and type of latrine, house construction mate-
rials (wall, roof and floor), number of rooms and density
of people per room. The first principal component was
used to generate the asset index, which was then di-
vided into quintiles. The indicators “percent of house-
hold with at least one net for every two people”and
“percent of population with access to a net within a
household”were calculated using the methods of Kilian
and colleagues [18].
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Ethics considerations
This protocol received ethical clearance from the Emory
University Institutional Review Board (IRB#00044684),
and the Nigeria Health Research Ethics Committee
[NHREC/01/01/2007]. Verbal informed consent to partici-
pate in the household and women’s interviews was sought
from heads of household or eligible women, respectively.
For blood testing, verbal informed consent was sought
from all eligible individuals older than 18 years of age or
from the parents of minors (0–17 years of age), as well as
additional verbal assent from minors over the age of six
years.
Results
Characteristics of study population
A total of 116 out of the selected 120 clusters were sam-
pled in Abia and Plateau States (Figure 1). Two clusters
each in Abia and in Plateau were not accessible due to
civil unrest or insecurity. Missing clusters were not re-
placed. Sampled clusters contained 1,426 households in
Abia (mean number of households per cluster: 24.6; range:
9–40) and 1,382 households in Plateau (mean number of
households per cluster: 23.8; range: 7–38). Of eligible
households, 121 (8.5%) in Abia and 47 (3.4%) in Plateau
were excluded from final analysis because no one was
present or because of refusal. This resulted in a study
population of 1,305 households in Abia and 1,335 in
Plateau.
Characteristics of surveyed households and individuals
are shown in Table 1. The mean number of individuals
per household and number of rooms used for sleeping
were lower in Abia than in Plateau. The mean elevation of
surveyed households was also significantly lower in Abia
(108.0 m; range: 11 m–351 m) versus Plateau (815.0 m;
range: 117 m–1344 m). Households in Abia were most
commonly (34.3%) classified in the highest wealth index
category, while households in Plateau were most com-
monly (28.0%) classified in the lowest wealth classification.
Most houses in Abia were made of cement or stone
block (81.4%), with a minor proportion built of mud and
sticks (14.2%) or mud bricks (2.8%), whereas in Plateau, a
greater diversity of construction types was observed be-
tween cement or stone blocks (40.9%), mud bricks
(33.7%), mud and stick construction (16.7%), and solid
brick construction (8.6%). The majority of roofs in both
Abia and Plateau were made of zinc or metal (87.4%,
70.9%, respectively) with the remained thatch/palm leaf
roofs (9.1%, 27.5%, respectively) or concrete/cement roofs
(1.0%, 1.1%, respectively).
Demographic data for the 14,057 individuals living in
the study households is also shown in Table 1. Age distri-
bution of individuals in surveyed households was generally
similar between states, as were the proportions of males,
females and self-reported pregnant women. There were
significantly more females (53.6%) than males (49.6%) in
Abia, but not in Plateau (49.5% and 50.5%, respectively).
Plasmodium prevalence
All children less than eleven years of age and individuals
of all ages in every third household were eligible for mal-
aria parasite testing by microscopy and rapid diagnostic
test (RDT). Microscopy results were available from 2,936
individuals in Abia and 4,209 individuals in Plateau. Over-
all age-adjusted prevalence of Plasmodium as detected by
microscopy was similar between Abia (36.1%, 95% CI:
32.3%–40.1%) and Plateau (36.6%, 95% CI: 31.3%–42.3%).
Crude prevalence by cluster ranged from 14.8% to 66.1%
in Abia and from 1.8% to 86.4% in Plateau (Figure 1).
Cluster prevalence was negatively, but poorly, associated
with elevation in Abia (r
2
=0.014)andPlateau(r
2
=0.142).
Table 1 Characteristics of study households and individuals
in Abia and Plateau states, Nigeria, September 2010
Abia Plateau
Number of clusters sampled 58 58
Household characteristics
Number of households sampled 1,305 1,335
Mean (SD) number of people per household 4.4 (2.7) 6.3 (3.1)*
Mean (SD) number of sleeping
rooms per household
1.9 (1.1) 2.4 (1.2)*
Altitude
≤100 m (%) 55.1 0.0*
100–1000 m (%) 44.8 46.3
>1000 m (%) 0.2 53.7*
Household wealth index, quintiles
Poorest (%) 6.9 28.0*
Second (%) 11.8 25.7*
Third (%) 21.2 17.0
Fourth (%) 25.9 18.0
Richest (%) 34.3 11.3*
Individual characteristics
Number of persons in sampled households 5,754 8,303
Age
<5 yrs (%) 14.7 16.4
5-9 yrs (%) 12.0 16.0*
10-14 yrs (%) 9.9 11.9
15-19 yrs (%) 9.3 9.8
20-49 yrs (%) 35.5 36.7
≥50 yrs (%) 18.6 9.3*
Proportion female (%) 53.6 49.6
Pregnant women, self-reported
(% of all individuals/% of women)
2.5/4.6 2.1/4.3
*Asterisk indicates statistically significant difference between states
(non-overlapping 95% confidence intervals).
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In Abia, 68.1% of infections were identified as Plasmo-
dium falciparum, 32.0% were Plasmodium malariae with
one instance of P. falciparum-P. malariae co-infection. In
Plateau, 98.7% of infections were P. falciparum,1.4%
P. malariae and two instances of co-infection. No Plasmo-
dium ovale infections were identified in either state. Preva-
lence of Plasmodium infection was significantly associated
with age in both Abia (χ
2
= 136.62, P < 0.001) and Plateau
(χ
2
= 326.45, P < 0.001), with prevalence highest in the 5–
9 year age group and lowest in those aged 50 years and
older (Figure 2). Infection was non-significantly higher
in males in both states, and significantly and inversely
associated with wealth in Abia (χ
2
= 122.96, P < 0.001)
and Plateau (χ
2
= 318.25, P < 0.001).
Blood samples were tested by RDT for on-site provision
of treatment for positive individuals. Concordant results
were obtained from 6,502 of 6,771 samples with valid
results for both microscopy and RDT (96.0% agreement;
κ= 0.919). Overall age-adjusted prevalence of Plasmodium
as determined by RDT was similar between Abia (30.4%,
95% CI: 25.7%–35.4%) and Plateau (32.4%, 95% CI:
26.6%–38.9%), with a significantly higher proportion of
non-P. falciparum infections in Abia (40.0%) than in Plat-
eau (0.7%), in line with microscopy results.
Anemia
Mean unadjusted hemoglobin among children less than
11 years of age was significantly lower in Abia (9.9 g/dL,
95% CI: 9.7–10.1 g/dL) versus Plateau (10.9 g/dL, 95%
CI: 10.6–11.2 g/dL). After adjusting for age and altitude,
more than half of children were anemic (any type) in
both states (Table 2), with anemia significantly more
prevalent in Abia (76.9%, 95% CI: 72.1%–81.0%) than in
Plateau (57.1%, 95% CI: 50.6%–63.4%). In Abia, there
was a significantly greater proportion of children with
both moderate anemia and severe anemia compared to
Plateau. Anemia was significantly more prevalent among
children less than 5 years (64.7%, 95% CI: 58.3%–70.6%)
compared to children five years and older (50.3%, 95%
CI: 43.0%–57.6%) in Plateau, with a similar trend ob-
served in Abia (80.5%, 95% CI: 75.1%–84.9%; 73.1%, 95%
CI: 67.4%–78.2%).
Malaria prevention measures
Less than one percent of households in Abia (0.4%) and
Plateau (0.6%) reported that indoor residual spraying
(IRS) with insecticide had been performed in the past
12 months (Table 3).
Household ownership of at least one bednet (of any type)
was 10.1% in Abia and 35.1% in Plateau. Only 2.1% of
households in Abia and 14.5% of households in Plateau
owned two or more nets. Likewise, 1.4% and 6.3% of all
households in Abia and Plateau, respectively, owned at least
one net for every two household members and 14.2% and
18.1% of households that owned nets in Abia and Plateau,
respectively, had enough nets for every two persons. While
net ownership was greatest among the highest wealth index
category in both states, there was not a significant associ-
ation between net ownership and quintiles of household
wealth index in either Abia (χ
2
= 9.01, P = 0.28) or Plateau
(χ
2
= 17.29, P = 0.17).
The mean number of nets per household was signifi-
cantly lower in Abia versus Plateau, whether considering
all households (0.1 nets versus 0.6 nets) or only those
households that owned at least one net (1.2 nets versus
1.7 nets), Table 3. The most frequently reported reasons
for not owning a net in households without nets include:
nets not available (56.3% in Abia, 44.3% in Plateau), nets
0
10
20
30
40
50
60
70
<5 5-9 10-14 15-19 20-49 >=50
Percent positive (%)
Age group (years)
Abia Plateau
Figure 2 Plasmodium prevalence. Proportion of individuals testing positive for Plasmodium infection by microscopy, by age group, Abia and
Plateau States, Nigeria, September 2010. In Abia, 68.1% of all infections were P. falciparum, 32.0% P. malariae with one co-infection; in Plateau,
98.7% of infections were P. falciparum, 1.4% P. malariae with two co-infections. Error bars are 95% confidence intervals.
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are too expensive (25.4%; 35.9%). Very few people re-
ported not liking nets (0.9% in Abia, 1.7% in Plateau) or
no mosquitoes (5.2%, 1.7%) as reasons for not owning
nets. Overall, 8.2% of the population in Abia and 23.8% of
the population in Plateau had access to a net within a
household, assuming a net is used by two people (Table 3).
As shown in Table 4, reported net use the night prior to
the survey among all individuals in all households was sig-
nificantly lower in Abia (3.4%, 95% CI: 2.1% –5.5%) versus
Plateau (14.7%, 95% CI: 11.3% –18.9%). Reported net use
was positively associated with wealth in Plateau (χ
2
=
172.67, P = 0.002), but not Abia (χ
2
=40.64, P=0.17). Re-
ported net use was also significantly associated with age in
both Abia (χ
2
= 29.93, P = 0.007) and Plateau (χ
2
=101.22,
P < 0.001), with net use highest among children less than
five years in both states (Figure 3). Reported net use was
significantly lower in Abia for all age groups except those
15–19 years. Reported net use among pregnant women
was also lower in Abia (5.7%) versus Plateau (21.0%).
There was no difference in net use between males and
females in either Abia (χ
2
= 1.35, P = 0.30) or Plateau (χ
2
=
1.92, P = 0.12).
The same trends were observed when restricted only to
households owning at least one net. Net use was lower in
Abia versus Plateau among all individuals (27.6%, 95% CI:
20.1%–36.6%; vs. 41.1%, 95% CI: 36.5%–45.9%, respect-
ively), children under five years (34.4% vs. 52.6%) and preg-
nant women (31.6% vs. 62.7%) (Table 4). In this smaller
subset, associations between net use and age (χ
2
= 11.25,
P = 0.14), gender (χ
2
= 1.30, P = 0.26) and wealth (χ
2
=
10.80, P = 0.50) were not evident in Abia. In Plateau, signifi-
cant associations with age (χ
2
= 143.79, P < 0.001) and
wealth (χ
2
= 67.09, P = 0.009), but not gender (χ
2
= 3.17,
P = 0.10) were observed.
Characteristics of nets observed in Abia (n = 150) and
Plateau (n = 807) are summarized in Table 5 along with
confidence intervals for all point estimates. The majority
of nets in both states were identified as LLINs, with a sig-
nificantly lower proportion in Abia (65.6%) versus Plateau
(89.5%). Baby nets (nets on a folding free standing wire
frame, suitable for placing over a sleeping infant) com-
prised a significantly greater proportion of all nets in Abia
(17.4%) compared to Plateau (0.5%). Approximately half of
all nets in Abia (49.4%) and Plateau (50.7%) were report-
edly obtained less than 12 months prior to the survey. In
Abia, nets were most frequently obtained from health fa-
cilities (37.0%) and markets (32.2%). Other sources include
shops (14.4%), received as a gift (8.7%), mass distribution
campaigns (4.4%), and community health worker apart
from mass distribution (2.2%). In Plateau, nets were also
most frequently obtained from markets (38.4%) and health
facilities (30.3%). The remainder were obtained from mass
distribution campaigns (17.4%), received as a gift (6.5%),
shops (2.4%), various other source (2.4%) and community
health worker (1.9%). Around half of all nets in both Abia
(49.0%) and Plateau (47.5%) were reportedly purchased.
The majority of nets in Abia (74.7%) and Plateau
(86.1%) were reportedly used at least once. The propor-
tion of nets hanging at the time of survey was signifi-
cantly lower in Abia (52.3%) compared to Plateau
(79.2%). Nearly all of the hanging nets in both states
Table 2 Anemia prevalence in children less than 11 years
of age in Abia and Plateau states, Nigeria, September 2010
Abia (n = 1,556) Plateau (n = 2,823)
% (95% CI) % (95% CI)
Normal
1
23.2 (19.0–27.9) 45.0 (38.2–52.0)*
Mild
2
16.1 (14.0–18.3) 18.5 (16.7–20.4)
Moderate
3
53.1 (47.8–58.3) 33.6 (28.1–39.5)*
Severe
4
7.8 (5.8–10.3) 3.0 (2.3–3.8)*
1
For age <5 years: hemoglobin [Hb] ≥11.0 g/dL; for age
5–11 years: Hb ≥11.5 g/dL.
2
For age <5 years: 10.0 g/dL < Hb < 11.0 g/dL; for age
5–11: 11.0 g/dL < Hb < 11.5 g/dL.
3
For age <5 years: 7.0 g/dL < Hb < 10.0 g/dL; for age
5–11: 8.0 g/dL < Hb < 11.0 g/dL.
4
For age <5 years: Hb <7.0 g/dL; for age 5–11: Hb <8.0 g/dL.
*Asterisk indicates statistically significant difference between states
(non-overlapping 95% confidence intervals).
Table 3 Household malaria prevention measures, Abia and Plateau states, Nigeria, September 2010
Abia (n = 1,305) Plateau (n = 1,335)
Percent of households that received IRS in past 12 months (95% CI) 0.4% (0.1–1.4) 0.6% (0.3–1.5)
Percent of households owning at least one net (95% CI) 10.1% (7.5–13.4) 35.1% (29.2–41.5)*
Percent of households owning two or more nets (95% CI) 2.1% (1.2–3.7) 14.5% (10.2–20.3)*
Percent of households with at least one net for every two people (95% CI) –all households 1.4% (0.8–2.1) 6.3% (3.8–8.8)*
Percent of households with at least one net for every two people (95% CI) –households
with at least one net
14.2% (8.8–19.6) 18.1% (13.3–23.0)
Mean number of nets per household (95% CI) –all households 0.1 (0.1–0.2) 0.6 (0.4–0.7)*
Mean number of nets per household (95% CI) –households with at least one net 1.2 (1.1–1.3) 1.7 (1.5–1.8)*
Percent of population with access to net within a household (assuming net used by two people) (95% CI) 8.2% (3.7-6.9) 23.8% (14.5-24.1)*
*Asterisk indicates statistically significant difference between states (non-overlapping 95% confidence intervals).
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(95.2%; 97.7%, respectively) were hung at an appropriate
height–i.e. able to be tucked in under sleeping mat on
floor or mattress on bed. The most commonly reported
reasons for not hanging nets in each state included: re-
spondent did not want to use net (40.0% in Abia, 28.4%
in Plateau), have not yet hung it (14.6%; 12.9%), were too
tired to hang it last night (9.1%; 5.6%) and don’t know how
to hang it (10.9%; 2.2%). Various other reasons were re-
ported by less than 10% of respondents as shown in Table 5.
Themajorityofnetswerereportedlyusedbyahousehold
member the previous night in Abia (60.6%) and Plateau
(80.4%), with use significantly higher in Plateau. Reasons
why nets were not used last night are listed in Table 5. No
single reason was reported by more than 18% of respon-
dents. The proportions of nets with holes were similar in
Abia (17.7%) and Plateau (16.5%), as were the proportions
of nets with mends (10.7%; 5.4%, respectively).
Additional reported methods used for protection
against mosquitoes or other nuisance insects include:
mosquito coils (used by 37.7% and 27.8% of households
in Abia and Plateau, respectively), canned insect spray
(31.4%; 22.9%), “Otapiapia”, an organophosphate-based
pesticide in liquid form (dichlorvos), approved for use in
grain storage areas but widely available locally from shops
and traders (19.5%; 38.6%; significantly higher in Plateau),
“Piff Puff”, a synthetic pyrethroid-containing insecticide
powder (9.9%; 12.8%). Other reported methods such as
burning leaves (<6% of households) and using repellent
soaps or creams (<1%) were uncommon in either state.
Discussion
This study was conducted in September 2010 prior to
planned mass distribution campaigns in Abia and Plateau
States, which took place in August 2012 and December
2010, respectively. The results document high levels of
Plasmodium infection and anemia in both states, extremely
low (<1%) IRS coverage and low bed net ownership and
use. Low IRS coverage across the sampled population is not
unexpected, as IRS in Nigeria is limited to ‘target’areas in-
cluding: densely populated municipalities, areas with short
malaria transmission seasons, areas where LLINs are diffi-
cult to implement, and institutional locations [5].
Table 4 Reported net use, Abia and Plateau states, Nigeria, September 2010
Abia Plateau
n% (95% CI) n% (95% CI)
All households
All individuals 5,754 3.4 (2.1–5.5) 8,303 14.7 (11.3–18.9)*
Children <5 years 853 6.0 (3.7–9.6) 1,384 19.1 (14.2–25.0)*
Pregnant women (self-reported) 129 5.7 (1.9–15.8) 186 21.0 (14.3–29.8)
Households owning at least 1 net
All individuals 648 27.6 (20.1–36.6) 3,161 41.1 (36.5–45.9)
Children <5 years 135 34.4 (24.2–46.2) 534 52.6 (44.2–60.9)
Pregnant women (self-reported) 19 31.6 (12.0–61.0) 72 62.7 (49.2–74.4)
*Asterisk indicates statistically significant difference between states (non-overlapping 95% confidence intervals).
0
5
10
15
20
25
30
<5 5-9 10-14 15-19 20-49 >=50
Percent (%)
A
g
e
g
roup (years)
Abia Plateau
Figure 3 Net use. Proportion of individuals who reported sleeping under a net the night prior to survey, by age group, Abia and Plateau States,
Nigeria, September 2010. Error bars are 95% confidence intervals.
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Around the same time (October 2010), the first national
malaria indicator survey (MIS) was conducted throughout
Nigeria in order to evaluate the scale-up of malaria pre-
vention and control measures [1]. While the MIS provides
national and zone-level estimates for interventions, state-
level evaluation is also critical as mass net distribution
campaigns are done on a state-by-state basis. In addition,
since state campaigns have been conducted in different
years, many of the 2010 MIS aggregate zonal estimates
combine data from states that had already completed mass
LLIN distribution with others that had not. As far as we are
aware, this study is the first to report baseline estimates of
malaria prevention measures, malaria prevalence and
anemia in individual Nigerian states prior to scaled–up
mass distribution campaigns targeting universal coverage.
Overall age-adjusted Plasmodium prevalence by mi-
croscopy (all ages) was similar between Abia (36.1%)
and Plateau (36.6%) with almost one third of infections in
Abia state being P.malariae. These represent some of the
only modern estimates of Plasmodium prevalence across
all age groups in Nigeria, as recent surveys including 2010
MIS tend to focus on specific sub-populations like chil-
dren [1,19,20], neonates [21,22], pregnant women [23], or
those infected with HIV [24-26]. Prevalence estimates for
children under five years by microscopy were similar for
Plateau (43.5%, 95% CI: 36.6%–50.7%) compared to the
2010 MIS estimate for the larger area of the North Central
zone in which it is located (49.4%, CI not reported), but
likely different in Abia (42.0%, 95% CI: 35.7%–48.6%) com-
pared to the 2010 MIS South East zone estimate (27.6%, CI
not reported) [1]. One recent study conducted among all
aged individuals during the dry season in Lagos State,
South West zone, estimated an overall prevalence of 14.7%,
Table 5 Net characteristics in sampled households, Abia
and Plateau states, Nigeria, September 2010
Abia
(n = 150)
Plateau
(n = 807)
% (95% CI) % (95% CI)
Net type
LLINs 65.6 (54.0–75.5) 89.5 (84.2–93.1)*
Pre-treated net 0.8 (0.1–5.8) 0.4 (0.1–1.4)
Untreated net 5.8 (1.1–25.0) 3.3 (1.9–5.7)
Other 0 0.3 (0.1–1.0)*
Don’t know or missing 27.8 (19.3–38.3) 6.5 (3.6–11.6)*
Proportion baby nets 17.4 (9.3–30.3) 0.5 (0.2–1.5)*
Net age
≤6 months 26.6 (18.5–36.5) 28.5 (20.2–38.6)
6-12 months 22.8 (13.7–35.4) 22.2 (16.9–28.5)
> 12 months 43.2 (32.8–54.1) 47.2 (39.6–55.0)
Don’t know or missing 7.5 (3.9–13.9) 2.1 (1.2–3.6)*
Source of nets
Market 32.2 (20.5–46.4) 38.4 (28.7–49.3)
Health facility 37.0 (24.2–51.9) 30.3 (22.1–40.1)
Mass distribution 4.4 (1.4–12.8) 17.4 (9.0–30.9)
Shop 14.4 (4.7–36.5) 2.4 (1.1–5.4)
Gift 8.7 (4.6–15.9) 6.5 (3.9–10.6)
Community health
worker (non-campaign)
2.2 (0.7–6.2) 1.9 (1.0–3.8)
Other 0.9 (0.2–3.6) 2.4 (1.0–6.0)
Proportion of nets purchased 49.0 (37.5–60.6) 47.5 (37.6–57.7)
Proportion of nets ever used 74.7 (64.5–82.7) 86.1 (80.0–90.5)
Proportion nets observed hanging 52.3 (40.9–63.5) 79.2 (72.5–84.7)*
Proportion of hanging nets
hung at appropriate height
95.2 (82.0–98.9) 97.7 (94.5–99.0)
Reasons why net was not hung
(multiple responses possible)
Do not want to use net 40.0 (22.5–60.5) 28.4 (16.2–44.8)
Have not yet permanently hung 14.6 (7.5–26.5) 12.9 (5.0–29.5)
Too tired to hang 9.1 (3.2–23.1) 5.6 (1.6–18.2)
Don’t know how to hang 10.9 (4.4–24.5) 2.2 (0.8–6.0)
Inconvenient 3.6 (1.0–12.6) 7.3 (3.4–14.8)
Too hard to hang 7.3 (1.8–25.6) 3.3 (1.2–9.2)
No space for net 5.5 (0.9–27.8) 2.8 (0.8–9.2)
Person responsible
for hanging absent
1.8 (0.2–12.4) 0.6 (0.1–4.3)
Other 20.0 (8.8–39.3) 31.4 (21.4–43.6)
Proportion nets used last night 60.6 (49.9–70.4) 80.4 (73.2–86.0)*
Reasons why net was not used last
night (multiple responses possible)
Usual user did not
sleep here last night
17.4 (8.2–33.3) 1.6 (0.5–5.3)*
Net not needed last night 4.4 (1.2–14.5) 14.1 (9.1–21.2)
Table 5 Net characteristics in sampled households, Abia
and Plateau states, Nigeria, September 2010 (Continued)
Cannot hang net 12.0 (6.1–22.3) 6.4 (3.0–13.1)
No mosquitoes 8.7 (3.9–18.4) 9.4 (3.4–23.7)
Net too old or torn 13.0 (6.2–25.5) 4.7 (1.9–10.9)
Net not available last
night (washing)
3.3 (0.4–21.2) 12.5 (6.2–23.8)
Too hot 10.9 (3.9–26.7) 3.3 (1.2–9.1)
Feel closed in or afraid 6.5 (1.8–21.3) 5.3 (1.2–19.9)
No malaria 0 5.7 (1.5–19.6)*
Net too dirty 4.4 (1.4–13.1) 0.6 (0.1–3.6)
Don’t like smell 2.2 (0.3–14.5) 2.6 (0.9–7.5)
Other 20.7 (11.4–34.5) 24.7 (14.8–38.3)
Don’t know 4.4 (0.9–19.4) 7.9 (2.8–20.4)
Proportion nets with holes 17.7 (10.1–29.2) 16.5 (12.0–22.2)
Proportion nets with mends 10.7 (4.1–24.8) 5.4 (3.5–8.4)
*Asterisk indicates statistically significant difference between states
(non-overlapping 95% confidence intervals).
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with prevalence highest in the 5–14 year age group [27].
This trend with age is consistent with our results, where
prevalence was highest in the 5–9and10–14 age groups in
both Abia and Plateau.
A high level of concordance was observed in Plasmo-
dium prevalence between microscopy and RDT, though
RDT-estimates were slightly lower than microscopy. This
contrasts with observations from other large surveys that
consistently observe higher RDT-prevalence attributed to
antigen persistence following treatment or submicroscopic
infections [28]. Differences between this study and MIS
2010 results in RDT-prevalence estimates for children
under five years were less pronounced than for micros-
copy results. However, unlike our study, which utilized a
Pf/Pan combination RDT, the MIS 2010 utilized Para-
check PF®, an RDT that only detects P. falciparum-specific
histidine-rich protein-2. MIS RDT results thus likely
underestimated the overall Plasmodium prevalence in
some areas through undiagnosed non-falciparum infec-
tions, as nearly one third of malaria infections in Abia in
the present study were identified as P. malariae by mi-
croscopy. A significant proportion of non-falciparum in-
fections were also identified by microscopy in South East
and North Central zones in the MIS 2010 [1]. Historically,
a significant proportion of P. malariae and P. ovale infec-
tions were also reported by The Garki Project, in Kano
State, North West zone, from 1969 to 1976 [29]. Taken to-
gether, these results demonstrate that non-falciparum in-
fections are prevalent in parts of Nigeria and highlight the
importance of utilizing multi-species RDTs to monitor
trends of all Plasmodium parasites. In addition to variation
in prevalence between species, our study highlights large
heterogeneity in prevalence between clusters within states
that deserves further investigation to improve malaria risk
stratification of all species in Nigeria.
In this study, more than half of children less than 11 years
in both states were found to be anemic (mild, moderate or
severe), with prevalence higher in Abia than in Plateau and
also higher among children less than 5 years. Our results
are consistent with WHO’s estimate that two-thirds of
preschool-age children in Africa are anemic [30], and
within Nigeria, are similar to those from the 2010 MIS,
which found 71.7% anemia prevalence in South East zone
and 56.0% in North Central zone among children under
five [1]. Malaria is a major cause of childhood anemia in
malaria endemic areas where it accounts for approximately
half of pediatric admissions for severe anemia [31,32].
Given the similar malaria prevalence between the two
states, it is not immediately clear why anemia was signifi-
cantly higher in Abia. Perhaps the higher prevalence of
P. malariae or the slightly longer malaria transmission sea-
son may contribute. Other causes of anemia include iron
and other nutritional deficiencies, blood disorders, inflam-
mation and other acute and chronic diseases [16]. Thus
differences in diet and genetic composition may also con-
tribute to higher anemia in Abia. However, we hypothesize
that repeated statewide MDA in Plateau, but not Abia, of
deworming drugs from 2003–2012 for the elimination of
lymphatic filariasis, as well as since 2008 for treatment of
schistosomiasis in school-age children [33,34], may have
reduced the prevalence of helminth infections that have
been shown to interact with malaria infection to worsen
anemia [35]. Indeed, a recent survey of school-aged chil-
dren has confirmed a higher prevalence of hookworm in-
fection in Abia compared to Plateau (D. Evans, personal
communication).
Prior to 2009, Nigeria’s policy was to provide free net
distribution to children under five and pregnant women
(vulnerable groups) only. As part of Nigeria’s aim to re-
duce by 50% malaria-related morbidity and mortality by
2013, the country embarked in 2009 on a strategy of
scaled-up mass distribution of universal coverage with free
long-lasting insecticidal net (LLINs) across the 36 states
and Federal Capital Territory. The new policy goal is to
reach at least 80% of households with an average of two
nets per household but the delivery of nets for these
scaled-up distributions, supported by The Global Fund
and other donors, took place over a five year period
(2009-2013) on a state-by-state basis.
The net ownership figures estimated here for both states
in 2010 are much lower than the current ministry target,
reflecting previous policy. In order to place our state-level
results in the context of previous net distribution strategy
and coverage estimates, we reviewed results from the
DHS 2003 [9] the study of Oresanya et al [36], the DHS
2008 [3], and the MIS 2010 [1] that reported zonal level
estimates. In the South East zone (a group of five states in-
cluding Abia, Figure 1), household net ownership of at
least one net of any type was 5.8% in 2003, reportedly in-
creased after scale up to 36.5% in 2005, decreased to
13.4% in 2008 and was up to 35% in MIS 2010. Our esti-
mate of ownership for Abia state only in 2010 (10.1%) was
surprisingly low, given that many more than 10% of
households would have a vulnerable group member. It
could be explained by 1) lack of net replacement since
2005, although we note that half of the nets in Abia in the
present study were less than one year old; or 2) inter-state
differences between Abia and other states within the
South East zone, perhaps mainly reflecting the mass distri-
bution in Anambra State that took place in 2009. Similar
review of net ownership in North Central zone (a group of
six states including Plateau, Figure 1), showed it to be
14.9% in 2003 [9], 19.0% in 2005 [36], 15.9% in 2008 [3]
and 32.7% in MIS 2010 [1]. The latter estimate was similar
to results of the current study in Plateau State only
(35.1%) and suggests a large increase in net ownership
from 2008 to 2010. Despite these similar estimates for
state and zone, intra-zonal differences between states also
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likely exist in North Central zone; for example scale up to
universal coverage occurred in 2009 in Niger State and
likely biased the zone estimate upwards. The higher own-
ership overall in Plateau may be partly due to efforts by
The Carter Center to increase and maintain net ownership
by integrating distribution with MDA for onchocerciasis
and lymphatic filariasis [10]. As in Abia, approximately half
of nets observed in Plateau were less than one year old.
The wide variation between states in both baseline coverage
and in past and future timing of scale up distribution high-
lights the importance of state-level surveys in evaluating
the impact of Nigeria’smassnetdistributionstrategy.
In both Abia and Plateau, household members had
taken the initiative to purchase about half of the nets cur-
rently owned, despite differences in wealth profiles be-
tween the two states. Around one-third of nets in both
Abia (37.0%) and Plateau (30.3%) had been obtained
through health facilities, although not all such nets were
provided free-of-charge: 9.8% and 19.4% of nets obtained
from health facilities in Abia and Plateau, respectively,
were reportedly purchased. One third of all nets were ob-
tained from markets or shops, indicating significant exist-
ing demand for nets prior to statewide mass distribution,
as was also observed in Enugu State, South East zone [37].
Unlike the present results, other studies of net ownership
in Nigeria have observed inequity prior to mass distribu-
tion campaigns, though with conflicting trends–some re-
port highest ITN ownership among wealthiest households
[3,38], while an earlier report found inverse associations
with wealth [9]. It will be important to document whether
demand for nets translates into sustained net use in
Nigeria once the access to free nets increases, as studies
from other African countries have revealed declines in net
use among households owning nets following mass distri-
bution campaigns [39,40].
Net use estimates follow similar trends to ownership.
Overall net use in 2010 estimated in this study for children
under five years and pregnant women in Abia (6.0%; 5.7%,
respectively) and Plateau (19.1%; 21.0%) was far below
ministry target of 80% for both populations. Past trends in
the South East zone for net use by children under five in
all households show it was 4.4% in 2003 [9], 16.0% in 2005
[36], 14.3% in 2008 [3] and 17.4% in MIS 2010 [1]. For
pregnant women in South East (not assessed in 2005) the
corresponding figures were 2% in 2003, 10.2% in 2008 and
12% in MIS 2010. These indicate substantial heterogeneity
in net use within the South East zone and that Abia was
lower than its zone average in 2010, although this is to be
expected given the low net ownership. In North Central
zone, trends in net use by under fives were fairly stable at
8.9% in 2003 [9], 7.3% in 2005 [36] and 9.7% in 2008 [3]
but doubled to 18.9% by MIS 2010 [1]. Pregnant women
showed a similar trend at 9.2% in 2003 and 9.4% in 2008
but greater increase by MIS 2010 to 36.7%. Thus Plateau
state was above average in net use by children under five
(19.1%) and below average for pregnant women (21.0%)
compared to its surrounding zone.
Among households that owned nets, net use by children
under five and pregnant women was five-fold higher in
Abia and 2.5- to 3-fold higher in Plateau compared to all
households; however, only about one third (in Abia) and
one half (in Plateau) of vulnerable groups reported sleep-
ing under a net the previous night. Yet 61.3% of nets in
Abia and 80.4% of nets in Plateau were reportedly used by
a household member last night, indicating that nets are
being used by persons other than children under five and
pregnant women within households, especially in Abia.
Use by other members is not surprising given that the
mean number of individuals per household in each state
exceeds by a factor of 3.7 the number of nets currently
available per household. Analysis of the early scale-up of
malaria prevention measures across sub-Saharan Africa
has shown that the primary driver of net use is the relative
availability of nets within households [41], and recent ap-
plication of additional MERG-recommended net indica-
tors to 2010 MIS data demonstrates that 61% and 71% of
households with an ITN in South East and North Central
zones, respectively, did not have enough nets for each
household member (defined as one ITN per two persons)
[18]. Using the same indicator, we found that 86% and 82%
of households with a net (of any type) in Abia and Plateau,
respectively, did not have sufficient number of nets.
Previous studies [38,41] have observed that net use
among children is not significantly associated with
household wealth after net distributions. In the present
study, which was conducted prior to mass distributions,
net use was positively associated with wealth in Plateau,
but not in Abia. Interestingly, DHS 2008 and MIS 2010
both reported inverse associations between wealth and
net use at the national level [1,3]. Also in contrast to
other studies, which reveal a female bias in net use in
Nigeria [1,42], significant differences between the sexes
were not observed in either state in the present study.
Age was significantly associated with net use among all
households in Abia and Plateau, which was highest in chil-
dren under five and those over 20 years. This is in agree-
ment with other surveys from Nigeria [1,38,42], which
consistently observe that net usage is lowest among older
children and young adults. This finding is very important
given that older children are the group with highest preva-
lence of Plasmodium infection. In addition to improving
access to nets, this points to a significant need for educa-
tion regarding malaria prevention and net use, including by
children over five years old. That this is needed even among
those who own nets is illustrated by the finding that ‘not
wanting to use net’was the most common reason for nets
not being hung last night and that 25% of nets in Abia had
never been used.
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In an effort to address these gaps, The Carter Center has
developed behavior change communication (BCC) mate-
rials that emphasize strategies for increasing net use that
were identified among consistent net users during focus
group discussions conducted in Plateau State. In addition,
BCC materials incorporate health education about lymph-
atic filariasis and malaria. This innovative, integrated
health messaging approach was driven by the fact that
both diseases share the same Anopheles vector and the be-
lief that heightened awareness of LF-associated sequelae,
which include swelling of the limbs (lymphedema, ele-
phantiasis) and genital organs (hydrocele), is likely to pro-
mote increased net usage, particularly among adolescents
and males.
As with any survey, there are limitations to note. Re-
sults from this study represent a single cross-sectional
sample, which was collected during peak malaria sea-
son. We compared results with the 2010 MIS survey,
which was conducted approximately one month after
our survey. However, the DHS surveys of 2003 and 2008
were conducted during the months of March to August
and June to October, respectively, which overlap periods
of typically lower malaria transmission. Care should thus
be taken when comparing our results with the DHS, par-
ticularly malaria parasite prevalence estimates, as well as
utilization of malaria prevention measures, since net use
has been observed to decline during dry seasons [43-45].
Studies of this type are also reliant upon self-reported data
for many questions. In an effort to verify net ownership
and ever-use of nets, survey teams visually inspected nets
within households and observed whether the net was still
sealed in its original packaging. However, it was not
possible to verify use of net the previous night or other
self-reported data. The survey was also conducted by inde-
pendent groups of survey teams in each state, and uniden-
tified sources of systematic error between teams may have
biased state level estimates and the inferred differences be-
tween states. Likewise, slides from Abia and Plateau were
read in separate laboratories. Although quality control was
conducted by the same individual for slides from both
states, systematic differences in initial slide reading be-
tween states could have occurred. Nonetheless, RDT data
closely matched the overall microscopy prevalence esti-
mates for each state, suggesting that gross errors between
states, and overall, did not exist.
Conclusions
Results from this study, which was conducted in September
2010 prior to planned mass distribution campaigns in Abia
and Plateau States, document high levels of Plasmodium
infection and anemia in both states, extremely low IRS
coverage and low bed net ownership and use. Mass LLIN
campaigns are expected to significantly improve access to
bednets for all at-risk Nigerians and follow-up surveys are
planned after distributions to evaluate progress toward
ministry targets for prevention measures and impact on the
disease burden of malaria.
Abbreviations
CI: Confidence interval; DHS: Demographic and health survey;
EA: Enumeration area; FCT: Federal capital territory; Hb: Hemoglobin;
IPTp: Intermittent preventative therapy in pregnancy; IRS: Indoor residual
spraying with insecticide; ITN: Insecticide-treated net; LLIN: Long-lasting
insecticidal net; MDA: Mass drug administration; MERG: Monitoring & evaluation
reference group; MICS: Multiple indicator cluster survey; MIS: Malaria indicator
survey; RDT: Rapid diagnostic test; SUFI: Scale-up for impact.
Competing interests
The authors declare that they have no competing interests.
Authors’contributions
AE, EE, EM, FOR, PME and PMG conceived the study. AS, AE, AEP, CO, EC, EE,
JD, OO and PMG trained survey teams. AE, AEP, AS, EE, IO, JA, KA, OUO, MU
and PMG conducted and supervised the survey. JN, JO, MO, PMG and SE
managed survey databases. JD supervised reading of blood films and
performed slide quality control, with assistance from KA. GSN, JN and PMG
analyzed data. RMD produced the map. GSN drafted the manuscript. AEP,
FOR and PMG contributed significant revisions to the manuscript. All authors
read and approved the final manuscript.
Acknowledgements
We thank all participants, survey staff, village volunteers and community
leaders for their assistance. We appreciate the efforts of all data entry staff
especially Ms Okpala Theresa. We also recognize the Nigerian National
Population Commission for assistance.
This study was funded by The Carter Center.
We are saddened by the recent untimely death of one of our co-authors,
Mr. Kal Alphonsus. He will be greatly missed.
Author details
1
The Carter Center, 453 Freedom Parkway, Atlanta, GA 30307, USA.
2
The
Carter Center, Jos, Plateau State, Nigeria.
3
The Carter Center, Southeast
Owerri, Imo State, Nigeria.
4
Plateau State Ministry of Health, Jos, Nigeria.
5
Abia State Ministry of Health, Umuahia, Nigeria.
6
University of Jos, Jos,
Nigeria.
7
Federal Medical Centre, Owerri, Imo State, Nigeria.
8
Federal Ministry
of Health, Abuja, Nigeria.
9
Current address: School of Public Health, Tropical
Medicine and Rehabilitation Sciences, James Cook University, Cairns, QLD,
Australia.
10
Current address: Agnes Scott College, Decatur, GA, USA.
Received: 27 November 2013 Accepted: 21 March 2014
Published: 26 March 2014
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doi:10.1186/1471-2334-14-168
Cite this article as: Noland et al.:Malaria prevalence, anemia and
baseline intervention coverage prior to mass net distributions in Abia
and Plateau States, Nigeria. BMC Infectious Diseases 2014 14:168.
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