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Environmental Factors Affecting Malaria Parasite Prevalence in Rural Bolifamba, South- West Cameroon

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The impact of some environmental factors on malaria parasite prevalence was investigated in rural Bolifamba, Cameroon. The study population comprised 1454 subjects aged 0 – 65 years. Malaria parasite prevalence was higher in the rainy (50.1%) than in the dry season (44.2%) with a significant difference (P=0.001) in mean parasite density between seasons. Individuals <15 years old, had significantly higher malaria parasite prevalence (55.5%) than those >15 years (37.4%). Malaria parasite prevalence (P=0.001) and parasite density (P=0.03) were higher in the individuals of wooden plank houses than those of cement brick houses. Inhabitants of houses surrounded by bushes or garbage heaps and swamps or stagnant water showed higher malaria parasite prevalence and densities compared with those from cleaner surroundings. Anopheles gambiae (63.8%) and A. funestus (32.8%) were associated with perennial transmission of malaria. Our data indicates that poor environmental sanitation and housing conditions may be significant risk factors for malaria parasite burden in Bolifamba.
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RESEARCH ARTICLE
African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006
40
Environmental factors affecting malaria parasite prevalence in rural
Bolifamba, South- West Cameroon
Theresa Nkuo-Akenji *, Nelson N. Ntonifor, Maze B. Ndukum , Helen K. Kimbi , Edith L. Abongwa,
Armand Nkwescheu, Damain N. Anong, Michael Songmbe , Michael G. Boyo , Kenneth N.
Ndamukong and Vincent P.K. Titanji
Faculty of Science, Department of Life Sciences, University of Buea, P.O. Box 63, Buea, South West
Province, Cameroon
* Corresponding author; Email: WIFON@YAHOO.COM
SUMMARY
The impact of some environmental factors on malaria parasite prevalence was
investigated in rural Bolifamba, Cameroon. The study population comprised
1454 subjects aged 0 – 65 years. Malaria parasite prevalence was higher in the
rainy (50.1%) than in the dry season (44.2%) with a significant difference
(P=0.001) in mean parasite density between seasons. Individuals <15 years old,
had significantly higher malaria parasite prevalence (55.5%) than those >15
years (37.4%). Malaria parasite prevalence (P=0.001) and parasite density
(P=0.03) were higher in the individuals of wooden plank houses than those of
cement brick houses. Inhabitants of houses surrounded by bushes or garbage
heaps and swamps or stagnant water showed higher malaria parasite prevalence
and densities compared with those from cleaner surroundings. Anopheles
gambiae (63.8%) and A. funestus (32.8%) were associated with perennial
transmission of malaria. Our data indicates that poor environmental sanitation
and housing conditions may be significant risk factors for malaria parasite
burden in Bolifamba.
[Afr J Health Sci. 2006; 13:40-46]
Introduction
Malaria is prevalent throughout Cameroon
with transmission being affected by climate
and geography [1,2], increased drug resistance
and the lack of adequate vector control
measures [3]. Reduction in man-vector contact
may be achieved by the use of protective
clothing, insect repellents, bed nets,
insecticides or environmental management. In
Zambia, multiple control interventions,
including environmental management against
Anopheles larval stages and improvement in
hygiene and sanitation reduced the overall
malaria incidence and mortality rates by
approximately 50% [4]. In Europe and North
America, malaria was eliminated through use
of insecticides and manipulation of the
environment [5]. Preliminary studies in
Bolifamba indicate that malaria transmission is
perennial [6] with Anopheles mosquitoes
occurring throughout the year. Factors
favouring mosquitoes may include the bushes,
garbage heaps, swamps and stagnant pools of
water that surround many houses in the
village. The poor housing conditions may also
encourage man-vector contact.
The study reported here therefore had as
the objective to investigate the effect of
entomological and environmental factors on
malaria parasite prevalence and parasite
density and provide information that could be
used by the public health sector for improving
its malaria control strategy.
Materials and Methods
Study site
Bolifamba is a village in South West
Cameroon at 247.89oN and 58.24oE and an
altitude of 530 on the east slope of Mount
Cameroon, 25 km from the Atlantic Ocean.
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African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006 41
It has a relative humidity of 80%, a
temperature range of 18oC – 23oC and an
annual rainfall of 4090mm. It has an equatorial
climate with a rainy season from March to
October and a dry season from November to
February but the rainfall pattern is changing
with rains beginning in June. A slow flowing
permanent stream flows across the village. A
low-lying marshy area that permits the
persistence of anopheline breeding year round
bound the village on the Southwestern side.
The inhabitants are of several ethnic groups
and the main occupation is farming. There are
two main house types – cement brick and
plank (wood) houses.
Parasitological studies
For malaria prevalence studies, 1454 subjects
of both sexes aged 0 – 65 years were selected
at random. Informed consent was obtained
from the parents and guardians of all minors.
In August 2002 (the peak transmission period),
208 children aged 0-14 years were selected to
assess the impact of housing and
environmental conditions on malaria
prevalence and parasite density. Ethical
clearance was obtained from the Provincial
Delegation of Public Health. Thick smears
were prepared, stained with Giemsa solution
and observed under 100X objective. Slides
were reported negative for parasites only after
observing at least 50 fields. Parasite density
was determined by counting the number of
malaria parasites against 200 white blood cells
and expressing the resultant number of
parasites/µl blood assuming a white blood cell
count of 8000 per µl of blood [7].
Entomology
Mosquitoes were collected by human landing
catches and spray catch in the dry and rainy
seasons. Eight adult volunteers served as
mosquito collectors as well as human baits,
half caught mosquitoes using aspirators in two
6 hourly shifts from 6 pm to 6 am from 8
houses each month. Spray catches were done
in 4 rooms per sector in 4 sectors of the village
every month. Rooms were sprayed with a
pyrethrum-based insecticide. Ten minutes after
spraying, adult mosquitoes were collected
from floor sheets. Adult Anophelines were
identified using the Gilles and de Meillon
morphologic identification keys. Human biting
rate (HBR) per person per night was calculated
from the human landing catches and the hourly
night biting pattern determined. Rainfall data
for the Bolifamba area was obtained from the
Cameroon Tea Estate.
Statistical analysis
All parasitological and entomological data was
analyzed with the statistical package for social
sciences (SPSS) [8]. Proportions were
compared using the chi-square or t-test. Means
were compared using analyses of variance
(ANOVA) while significant levels were
measured at 95% confidence level with
significant differences recorded at p<0.05.
Results
Malaria prevalence and parasite density
Six hundred and forty one males and 813
females aged 0-65 years were examined. No
significant difference (p = 0.75) in the
prevalence of malaria parasite was observed
between males (46.1%) and females (47.0%).
Malaria parasite was prevalent throughout the
year but was significantly higher in the rainy
season [50.1% (284/567)] than in the dry
season [44.2% (392/887)] (χ2 =4.8; P = 0.028).
Parasite density ranged from 38 – 50252
parasites/µl blood. The geometric mean
parasite density was 470±9318 and 414±432
parasites/µl blood for the rainy and dry season
respectively, and this difference was also
significant (t = 0.86; df = 1; P = 0.001).
Malaria parasite prevalence and mean parasite
density declined after age 14 (Table 1).
Prevalence in children from 0-14 years was
55.5% and in adults 15-65 was 37.4%
(P<0.05). Mean parasite density was higher in
subjects aged 0-14 year than in those 15-65
years old (Table 1).
Entomological observations
A. gambiae and A. funestus were both
predominant through out the year but the
population of the former was higher during the
rainy season while the later was higher in the
dry season. Two thousand six hundred and
thirty mosquitoes were collected by the human
landing catches and 442 by the spray catch
technique (Table 2). The biting cycles of all
Anopheles species showed peak biting hours
between 1-2a.m. and 2-3a.m. irrespective of
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African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006
42
season (Fig 1A & 1B). Biting rates were
higher for A. gambiae than for other species.
The rainfall data is shown on Fig. 2 with peak
rainfall occurring in the months of July and
August. There was more biting during the
rainy season than in the dry season
Table 1: Malaria parasite prevalence and geometric mean parasite density (GMPD) by
age group.
Age group
(years)
Number
infected
Prevalence
(%)
GMPD
(Parasites/µl blood ± SD)
0-1 37(75)* 49.3 2915 ± 8727
2-5 173(261) 66.3 3469 ± 12069
6-9 96(193) 49.7 1437 ± 5233
10-14 95(190) 50.0 1081 ± 5673
15-65 275(735) 37.4 328± 777
Malaria prevalence: At 95% confidence level, χ2 = 67.44; df = 4; P = 0.00
Mean parasite density F = 2.94; df = 4, P = 0.0006
*(Total number of individuals tested per age group)
Table 2: Percent Anopheline abundance (n).
Seasons
Rainy season Dry season
Spray catch technique
A. gambiae 46.2* 41.4
(97)** (96)
A. funestus 52.4 56.0
(109) (130)
A. hankocki 1.4 2.6
(3) (6)
Total 100 100
(209) (2320
Human landing catch
technique
A. gambiae 66.8 44.5
(584) (66.2)
A. funestus 32.4 50.3
(283) (747)
A. hankocki 0.8 5.2
(7) (77)
Total 100 100
(874) (1486)
* (Percentage of mosquitoes caught)
** (Numbers caught)
Of the 117 houses examined, 31(26.5%) were
built with cement bricks and 86 (73.5%) with
wooden plank. The average number of
occupants per house was 7. Ceilings were
present in 20.5% cement brick and 11.9%
wooden plank houses. However, the presence
of a ceiling did not have any influence on
parasite density. The malaria parasite
prevalence for children living in wooden plank
and cement brick houses was 62.7% and
45.4% respectively and the difference was
significant (χ2 =13.56; P =0.00). The geometric
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African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006 43
mean parasite density was 5117±6682 and
3550±4622/µl blood for children living in
wooden plank and cement brick houses
respectively (χ2 = 9.5; P = 0.025). Children
living in houses in which bed nets were not
used had higher malaria parasite prevalence
than those who used bed nets (67.5% versus
45.5%;χ2=5.57;P=0.02).
Effect of environmental conditions on
malaria parasite
Malaria parasite prevalence and parasite
density was higher in children living in houses
surrounded by bushes/garbage and
swamps/stagnant pools of water (Tables 3 and
4 respectively) when compared with those
inhabiting cleaner environments. There was a
high positive correlation between swamps and
stagnant pools and malaria parasite prevalence
(r = 0.82; P = 0.001) while bushes and garbage
were not highly positively correlated (r = 0.56;
P= 0.001).
Fig. 1. Anopheles species peak biting hours in the rainy (A) and in the dry (B) seasons
A
A
A
B
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
6-7pm
8-9pm
9-10pm
10-11pm
11-12pm
12-1am
1-2am
2-3am
3-4am
4-5am
5-6am
Hour interval
Biting cycle (mosquito/man/hour)
An. funestus
An. gambiae
An. hankocki
0
0.2
0.4
0.6
0.8
1
1.2
6-7pm
8-9pm
9-10pm
10-11pm
11-12pm
12-1am
1-2am
2-3am
3-4am
4-5am
5-6am
Hour inte rval
Biting cycle (mosquito/ man /hour)
An. funestus
An. gamb iae
An. hankock i
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African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006
44
Table 3: Association of environmental factors with malaria parasite prevalence.
Environmental Factor 1Present
2Absent χ2 d.f. P
Bushes/garbage *69.7%(69/99) 47.7%(52/109) 10.31 3 0.00
Swamps/Stagnant pools
of water
72.6%(61/84)
48.4%(60/124)
12.09
3
0.00
Bushes/garbage and
swamps/Stagnant pools
of water
60.5%(26/43)
35.0%(7/20)
6.0
3
0.04
1Presence of environmental condition
2Absence of environmental condition
*Malaria prevalence
Table 4: Association of environmental factors with parasite density
Swamps/stagnant pools of
water
Bushes/garbage Swamps/ stagnant pools
of water and
bushes/garbage
Parasite
density
Present Absent
Present Absent
Present Absent
> 10.000 28*(45.9%) 10(16.7%) 20(29.0%) 18(34.6%) 10(38.5%) 0(0.0%)
> 1000 2(3.3%) 13(21.7%) 8(11.6%) 7(13.5%) 6(23.1%) 3(42.9%)
> 400 12(19.7%) 27(45.5%) 30(43.5%) 9(17.3%) 7(26.9%) 2(28.6%)
1-399 19(31.1%) 10(16.7%) 11(15.9%) 18(34.6%) 3(11.5%) 2(28.6%)
Total 61 60 69 52 26 7
χ2
d.f.
25.14
3
10.99
3
5.0
3
P 0.001 0.012 0.015
* Number of positive cases
Relationship between anopheles species
abundance with malaria
A high Anopheles species population
corresponded with higher malaria parasite
prevalence and parasite density. A positive
correlation was recorded between total
Anopheles population and malaria parasite
prevalence (r = 0.50; P = 0.001) as well as
mean parasite density (r = 0.51; P= 0.001).
Discussion
Malaria parasite prevalence differed between
age groups with the highest prevalence in
children less than 15 years old (55.5%). Lower
mean parasite densities were recorded in
adults than in children. This accord with
similar studies conducted in Bamenda, Douala
and Yaounde, [9] and has been attributed to
protective immunity as a result of previous
exposure to malaria.
Entomological surveys conducted in our
study revealed that A. funestus and A. gambiae
were the predominant Anopheles species and
malaria transmission vectors in Bolifamba. In
many areas of Africa, Anopheles gambiae is
found together with an equally important
vector A. funestus [10]. A. gambiae accounted
for about 68% of adult human bait catches, in
both the rainy and dry seasons. A. funestus was
the most populated species caught during
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African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006
45
spray catches (done indoors) for both seasons.
A low A. hankocki population was recorded in
this study. This species has been reported to be
a secondary vector in malaria transmission and
will effect transmission in the presence of the
main transmission vectors [11].
The seasonal variation in malaria parasite
prevalence in Bolifamba can be attributed to
changes in Anopheles abundance during the
year. High rainfall in the rainy season (Fig. 2)
produced pools and swamps due to poor
drainage, producing suitable conditions for
mosquitoes. In the dry season, the formation of
water pools around some public water taps due
to poor drainage, coupled with much sunlight
was conducive to breeding of A. gambiae
[12,2]. Thus the persistence of some swamps,
together with the existence of bushes or
plantains that surround many households
which serve as resting sites for these
mosquitoes during the dry season leads to high
exposure to mosquito bites and risk of malaria
parasite infect all year round.
Houses built with plank had breaks and
crevices on the walls and ceiling boards that
provided refuges and allowed for easy passage
of mosquitoes. This may explain why more
mosquitoes were caught in plank houses than
brick houses and the higher malaria parasite
prevalence in children living in plank versus
brick houses.
Bed nets were shown to be protective
but most of them were old and some torn,
which explain why children in houses where
bed nets were used still had relatively high
malaria prevalence. None of the bed nets were
treated with insecticides. The presence of
ceiling boards in some houses did not reduce
malaria parasite prevalence as the boards did
not completely cover the roof or had cracks in
them, which served as passage ways for
mosquitoes
Figure 2. Mean rainfall data (mm) for 2001 and 2002.
The impact of environmental surroundings on
malaria prevalence was potentially important
the highest malaria prevalence being recorded
in children living in houses surrounded by
bushes and swamps. High Anopheles species
populations were caught from these
environments. A reduction of malaria
transmission in this area might be achieved by
control interventions involving environmental
management alongside the use of bed nets [4].
Implementation of an environmental control
programme could be achieved by improving
drainage of flooded areas and swamps and
through campaigns to clear bushes and
disposal of garbage (such as building local
incinerators). House improvements should
take into consideration the sealing off of
crevices and breaks in the walls and roof.
0
5
10
15
20
25
30
J. F. M. A. M. J. J. A. S. O. N. D. J. F. M. A. M. J. J. A. S. O. N. D.
Months
Mean rainfall(mm)
Mean rainfall(mm)
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African Journal of Health Sciences, Volume 13, Number 1-2, January-June 2006
46
Acknowledgements
We thank the University of Buea for providing
a malaria research laboratory for our team.
Thanks also go to the Chief and the entire
population of Bolifamba for participating in
the study. This investigation received financial
support from UNDP/World Bank/WHO
Special Programme for Research and Training
in Tropical Diseases.
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Background: Malaria is a major public health problem in sub-Saharan Africa. Several efforts are being made to reduce its prevalence and morbidity in Nigerian children with emphasis on vector control measures. Methods: This was a cross-sectional descriptive study conducted on 382 febrile children seen at a tertiary hospital in Nigeria over an eight-month period. A structured questionnaire was used to collect information on socio-demographic, vector control measures and care given to the subjects. Investigations conducted included malaria microscopy and total leukocyte count. Results: Eighty percent (308/382) employed at least one vector control measures to prevent malaria infection, and majority 232 (75.2%) use only one control measure. The commonest control measures used included always keeping doors and windows shut 298 (96.7%) and/or netted 280 (90.9%), use of conventional insecticide sprays 183 (59.4%), use of insecticide treated bed nets (ITNs) 178 (57.8%) and ensuring child sleeps at night with body adequately covered 77 (25%). Approximately half (178/315) of households who owned ITN used it, and only 40.4% (72/178) used it daily. It was noted that children that slept under an insecticide treated bed net (RR 0.56, 95% CI 0.33-0.94; P=0.029) and those who slept well covered at night (RR 0.26, 95% CI 0.12-0.61; P=0.002) had less risk of malaria infection. The use insecticide treated bed net however lost significance following adjustment for other control measures used and socio-demographic factors of interest (RR 0.63, 95% CI 0.36-1.10; P=0.101). Conclusion: There is need to intensify education on appropriate malaria control measures especially proper use of insecticide-treated nets and suitable clothing during sleep at night. Keywords: Malaria prevention, insecticide treated net, hospitalized children
... As, some studies have suggested that poor environmental sanitation and housing conditions are major source of malaria spreading. Beside this, lack of appropriate control measures might be significant risk factors for malaria parasite burden (Nkuo-Akenji et al., 2008). ...
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Malaria is one of the main causes of morbidity and mortality in developing countries like Pakistan. Current study is based on geospatial analysis of malaria across Bahawalpur district of Pakistan. The key purpose is to measure spatial patterns which might be helpful for generating local environmental etiological hypothesis for malaria. Union council level epidemiological data for malaria was collected through 115 health centers from the study area for the period of six years 2012–2017. Techniques of spatial autocorrelation were applied to find results. Local Moran’s I statistics was used to perform cluster and outlier analysis of malaria. Presence of local clustering was further assessed by using Getis Ord Gi* statistics to assess intensity of hotspots and cold spots at the union council level. However, Inverse Distance Weighing (IDW) was used to interpolate and predict the spatial pattern of malaria cases in study area. Results showed spatial heterogeneity of malaria incidence in the district identifying both high (hotspots) and low (cold spots) clusters. Highest statistical significance has been revealed in northwestern rural areas of the district defining them as malaria hotspots. Contrary, extreme northern areas and urban centers of tehsils were found to be cold spot during all the six years. Finally, this study provides also a set of suggestions addressing the local environmental issues and to minimize the incidence of malaria through administrative environmental management and community participation. In addition, it will not only provide a base for advance geospatial research of malaria but can also be applied in other malaria endemic districts of the country.
... The specific locations of the countries constituted the societal factor. Due to the strong association between survival of mosquitos or incidence of malaria and geographical/climatic factors [46][47][48], the countries were categorised based on their specific location within Africa as defined by the United Nations [49]. These are Western (Benin, Burkina Faso, Ghana, Guinea, Liberia, Mali, Niger, Sierra Leone, Togo), Eastern (Burundi, Kenya, Malawi, Mozambique, Tanzania, Uganda, Zambia, Zimbabwe), Central (Congo DR, Gabon, Guinea) and Southern (Namibia). ...
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Background Malaria in pregnancy is a crucial public health concern due to the enormous risk it poses to maternal and newborn health. The World Health Organisation therefore recommends insecticide-treated net (ITN) for pregnant women. The world over, sub-Saharan Africa bears the highest prevalence of malaria and its associated complications. This study investigated the individual, community and society level factors associated with ITN use among pregnant women in sub-Saharan Africa. Methods The study was conducted with Demographic and Health Survey data of 21 sub-Saharan African countries. A total of 17,731 pregnant women who possessed ITN participated in the study. Descriptive computation of ITN use by survey country and socio-demographic characteristics was conducted. Further, five multi-level binary logistic regression models were fitted with MLwiN 3.05 package in STATA. The Markov Chain Monte Carlo (MCMC) estimation procedure was used in estimating the parameters whilst the Bayesian Deviance Information Criterion was used for the model fitness test. Results On average, 74.2% pregnant women in SSA used ITN. The highest prevalence of ITN use occurred in Mali (83.7%) whilst the least usage occurred in Namibia (7%). Women aged 30–34 were more likely to use ITN compared with those aged 45–49 [aOR = 1.14; Crl = 1.07–1.50]. Poorest women were less probable to use ITN relative to richest women [aOR = 0.79; Crl = 0.70–0.89]. Compared to women who did not want their pregnancies at all, women who wanted their pregnancies [aOR = 1.06; Crl = 1.04–1.19] were more probable to use ITN. Women in male-headed households had higher likelihood of ITN use compared to those from female-headed households [aOR = 1.28; Crl = 1.19–1.39]. On the whole, 38.1% variation in ITN use was attributable to societal level factors whilst 20.9% variation was attributable to community level factors. Conclusion The study has revealed that in addition to individual level factors, community and society level factors affect ITN use in SSA. In as much as the study points towards the need to incorporate community and societal variations in ITN interventions, active involvement of men can yield better outcome for ITN utilisation interventions in SSA.
... Morbidity was significantly higher in May, June, July, and August compared to the other months in the Penka Michel Health District. This result concurs with that of (Chiabi et al. 2020;Atangana et al. 2009;Nkuo-Akenji et al. 2006) where the highest transmission rate in Cameroon was during the rainy season. ...
... S6). In November, warmer and to some extent wetter conditions are likely to result in a proliferation of diverse microbial threats , as well as vectors (Ortego and Espada 2007;Wood et al. 2007;Nkuo-Akenji et al. 2008). Increased levels of natural antibodies enhance a host's ability to detect novel pathogens and an increase in NAbs during this season could be advantageous ...
Thesis
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Animal immune systems are essential for defence against parasitism and disease. Immune functions are costly because they require resources to operate and can cause collateral damage to an organism’s own cells. These costs are important when resources are finite because they may result in physiological trade-offs between immune function and other costly processes like reproduction, in order to maximise individual fitness. In theory, there should be some level of optimal immune function, but this could be highly context-dependent, and there is much unexplained variation between individuals. In this thesis I aim to investigate individual variation in constitutive innate immunity (baseline immune defences) and (1) how it can be driven by environmental factors, (2) how it varies with age within and between individuals, and (3) how it can ultimately affect individual fitness outcomes. My study species, the purple-crowned fairy-wren (Malurus coronatus) is a sedentary, resident species of northern Australia. The species lives in social groups occupying stable year-round territories which provides an exceptional opportunity to gather detailed information about the immediate environment, life-histories, and reproductive outcomes for every single studied individual. By quantifying immune function in individuals through repeated captures and sampling, I am able to associate the individual’s immune status to the detailed information about of their lives to gather an insightful observational perspective on the possible causes and consequences of individual variation in immune function. Firstly (chapter 2), I find that social and ecological variables are relatively unimportant compared to short-term climatic variables, which have the strongest relationships with immune function and stress. Immune function remained relatively stable relative to long term seasonal environmental variation. Consequently, immune function may be more susceptible to short-term environmental perturbations, and fairy-wrens may be anticipating predictable seasonal change and moderating their immune investment to maintain baseline function. Secondly (chapter 3), I use multiple repeated measures of immune function from individuals to assess age-related changes over time. I find limited evidence of immunosenescence (a decline in immune function with age), in addition to evidence of immune maintenance of some immune components. These results suggest that self-maintenance roles of immune components beyond parasite defence could become more important with age. In chapter 3, I also demonstrate how longitudinal studies are important for discerning individual and population level trends. Lastly (chapter 4), I find that a higher probability of survival is not related to higher levels of immune function, but I also find some evidence that optimal immunity is context-dependent. I do not find any evidence of trade-offs between immune function and reproductive output, but instead that individual quality might override trade-offs. I also find that chronic stress and body condition do not strongly relate to fitness outcomes in ways that support hypotheses regarding environmental stressors and resource availability. Maintaining baseline levels of immune components does not appear to be costly for fitness in these fairy-wrens. In the final chapter of my thesis, I discuss the possibility of immune component-specific trade-offs and immunoplasticity emerging from the context-dependency of immune function, in addition to suggested directions for future research.
... The likelihood ratio of 2.14 also confirms an association between malaria and the draining of stagnant water in Foumbot. A dirty environment has been reported to increase malaria transmission [66][67][68][69][70]. Although Foumbot and Bamendjou are both rural areas, unlike Foumbot, Bamendjou municipality is committed to environmental sanitation. ...
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Background Although a significant decrease in entomological and epidemiological indicators was reported in Cameroon since the introduction of insecticide-treated bed nets, malaria prevalence remains high also in some parts of the West Region of Cameroon. This study was designed to evaluate malaria preventive measures among patients attending the Bamendjou and Foumbot District hospitals of the West Region of Cameroon. Methods This was a cross-sectional study carried out within a period of 3 months, from January to March 2020. Data was obtained using a structured questionnaire and laboratory analysis. The CareStart ™ Pf Malaria HRP2 qualitative rapid diagnostic test was used for malaria diagnosis. The questionnaire was designed to collect information on respondent’s socio-demographic characteristics, and the use of malaria preventive measures. Data were analysed using descriptive statistics, regression analysis, and Chi-square (and Fisher’s exact) test. Results A total of 170 study participants were recruited in Foumbot and 197 in Bamendjou. Malaria was significantly (P < 0.0001) more prevalent in Foumbot (47.06%) than in Bamendjou (19.8%). In Foumbot, non-use of insect repellent spray (P = 0.0214), insect repellent body cream (P = 0.0009), mosquito spray (P = 0.0001) and not draining stagnant water (P = 0.0004) predisposed to higher risk of malaria. In Bamendjou, non-use of insect repellent spray (P = 0.0012), long-lasting insecticidal bed nets (P = 0.0001), window and door nets (P = 0.0286), predisposed to a higher risk of malaria. Conclusions Malaria prevalence was high among the study participants especially in Foumbot. An adequate follow-up to ensure effective execution of the recently launched third phase of LLINs distribution campaign in Cameroon is recommended. Additionally, integrated vector management is required to ensure effective control of malaria transmission in Foumbot and Bamendjou.
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