| Literature DB >> 35895353 |
Manfred Accrombessi1, Martin C Akogbeto2, Edouard Dangbenon2, Hilaire Akpovi2, Arthur Sovi1, Boulais Yovogan2, Constantin Adoha2, Landry Assongba2, Aurore Ogouyemi-Hounto3, Germain Gil Padonou2, Charles Thickstun4, Mark Rowland1, Corine Ngufor1, Natacha Protopopoff1, Jackie Cook5.
Abstract
Malaria remains the main cause of morbidity and mortality in Benin despite the scale-up of long-lasting insecticidal nets (LLINs), indoor residual spraying, and malaria case management. This study aimed to determine the malaria burden and its associated risk factors in a rural area of Benin characterized by high net coverage and pyrethroid-resistant mosquito vectors. A community-based cross-sectional survey was conducted in three districts in southern Benin. Approximately 4,320 randomly selected participants of all ages were tested for malaria using rapid diagnostic tests within 60 clusters. Risk factors for malaria infection were evaluated using mixed-effect logistic regression models. Despite high population net use (96%), malaria infection prevalence was 43.5% (cluster range: 15.1-72.7%). Children (58.7%) were more likely to be infected than adults (31.2%), with a higher malaria prevalence among older children (5-10 years: 69.1%; 10-15 years: 67.9%) compared with young children (< 5 years: 42.1%); however, young children were more likely to be symptomatic. High household density, low socioeconomic status, young age (< 15 years), poor net conditions, and low net usage during the previous week were significantly associated with malaria infection. Malaria prevalence remains high in this area of intense pyrethroid resistance despite high net use. New classes of LLINs effective against resistant vectors are therefore crucial to further reduce malaria in this area.Entities:
Year: 2022 PMID: 35895353 PMCID: PMC9490648 DOI: 10.4269/ajtmh.22-0190
Source DB: PubMed Journal: Am J Trop Med Hyg ISSN: 0002-9637 Impact factor: 3.707
Baseline characteristics of the study population
| Characteristics | Proportion or mean | |
|---|---|---|
|
| ||
| Number of clusters | 60 | |
| Number of households per cluster | Mean (range) | 904 (82–5403) |
| Proportion of children under 10 years per cluster, % | Mean (range) | 30.9 (25–35.2) |
| Cluster with high socioeconomic status, % (n) | Yes | 62.7 (37) |
|
| ||
| Number of households enrolled | 3,027 | |
| People living in the household | Mean (± SD) | 5.3 (±2.6) |
| Number of sleeping spaces | Mean (± SD) | 2.7 (±1.3) |
| Head of household gender, % (n) | Male | 83.4 (2,525) |
| Female | 16.6 (502) | |
| Head of household education level, % (n) | No education | 71.4 (2,160) |
| Primary education | 17.2 (521) | |
| Lower secondary education | 7.3 (220) | |
| Higher secondary education | 2.7 (81) | |
| College/University | 1.4 (45) | |
| Ethnic group, % (n) | Fon | 77.2 (2,336) |
| Other* | 22.8 (691) | |
| Presence of potential breeding sites, % (n) | Yes | 76.9 (2,209) |
|
| ||
| Number of participants enrolled | 4,441 | |
| Participant gender, % (n) | Male | 49.1 (2,182) |
| Female | 50.8 (2,259) | |
| Age, years % (n) | ≤ 5 | 16.5 (735) |
| 5–10 | 14.4 (638) | |
| 10–15 | 13.6 (606) | |
| > 15 | 55.4 (2,462) | |
| Education level, % (n) | Not in the age of education | 16.5 (735) |
| Not educated | 52.5 (2,333) | |
| Educated | 30.9 (1,373) | |
SD = standard deviation.
Other ethnic groups: Mahi, Holli, Yoruba, Goun.
Characteristics of long-lasting insecticidal nets presented in the household
| Characteristics | Proportion or mean | |
|---|---|---|
|
| ||
| Number of households enrolled | 3,027 | |
| Household net ownership, % (n) | Yes | 95.8 (2,902) |
| Household net access, % (n) | Yes | 55.9 (1,691) |
| Population net access, % (95% CI) | Yes | 79.5 (78.9–80.1) |
| Number of nets (any type) in the household | Mean (±SD) | 2.5 (±1.3) |
| Number of LLIN in the household | Mean (±SD) | 2.3 (±1.3) |
|
| ||
| Number of participants enrolled | 4,441 | |
| Number of participants enrolled with a net | 4,088 | |
| Number of participants enrolled with an LLIN | 3,949 | |
| Origin of LLIN, % (n) | National campaign (2017) | 91.0 (3,595) |
| Healthcare facility (ANC) | 6.4 (251) | |
| Healthcare facility (EPI) | 1.6 (65) | |
| Public market | 0.4 (16) | |
| Other | 0.6 (22) | |
| Proportion of LLIN observed, % (n) | Yes | 99.0 (3,910) |
| Type of LLIN, % (n) | PermaNet 2.0 | 64.3 (2,489) |
| Dawa plus | 9.6 (374) | |
| Olyset Net | 7.0 (271) | |
| Duranet | 1.4 (53) | |
| Yorkool | 0.5 (21) | |
| Other* | 5.7 (221) | |
| Unknown | 11.4 (443) | |
| Duration usage of LLIN, % (n) | ≤ 1 year | 7.2 (286) |
| 2 years | 64.3 (2,540) | |
| 3 years | 21.1 (833) | |
| > 3 years | 7.3 (290) | |
| LLIN conditions, % (n) | Good | 18.9 (732) |
| Average | 43.2 (1,671) | |
| Poor | 37.9 (1,468) | |
| Population LLIN use, % (n) | Yes | 95.8 (3,782) |
| Net usage the week before the visit, % (n) | All nights | 88.4 (3,490) |
| Most of the nights | 8,6 (338) | |
| Few nights | 3.1 (121) | |
ANC = antenatal care visit; EPI = expended program immunization; LLIN = long-lasting insecticidal net; SD = standard deviation.
Most important other types of bed nets observed were impregnated by deltamethrin (88.2%, 195/221).
Malaria indicators in the study population
| Characteristics | Proportion % (n) | |
|---|---|---|
| Number of participants enrolled, n | 4,441 | |
| History of fever in the past 48 hours | Yes | 12.6 (562) |
| Fever* at the time of visit | Yes | 8.0 (356) |
| Hemoglobin test performed among children under 5 years | Yes | 99.5 (731) |
| Anemia† among children under 5 years old | Yes | 75.9 (555) |
| Malaria rapid diagnostic test performed | Yes | 99.7 (4,428) |
| Malaria infection | Yes | 43.5 (1,924) |
| Malaria infection by age category | ≤ 5 years | 42.1 (309) |
| 5–10 years | 69.1 (440) | |
| 10–15 years | 67.9 (410) | |
| > 15 years | 31.2 (765) | |
| Proportion of symptomatic cases‡ among infected per age | ≤ 5 years | 33.3 (103/309) |
| 5–10 years | 28.9 (127/440) | |
| 10–15 years | 23.7 (97/410) | |
| > 15 years | 19.2 (147/765) | |
| Proportion of malaria among participants with fever or history of fever in the past 48 hours | Yes | 57.3 (474) |
Fever: infrared frontal temperature ≥ 37.5°C.
Hemoglobin (Hb) < 110 g/L.
Symptomatic cases: defined by the presence of malaria infection without fever or history of fever in the last 48 hours.
Risk factors associated with malaria infection in an area of pyrethroid-resistant vectors in Benin
| Factors | Malaria positive % (n) | Univariate analysis | Multivariate analysis | |||
|---|---|---|---|---|---|---|
| OR* (95% CI) | aOR† (95% CI) | |||||
|
| ||||||
| People living in the household | < 3 | 29.2% (148) | 1 | 1 | ||
| 3–7 | 43.8% (1,382) | 1.82 (1.47–2.24) | < 0.001 | 1.29 (1.01–1.65) | 0.03 | |
| > 7 | 51.6% (394) | 2.36 (1.84–3.02) | 1.47 (1.10–1.96) | |||
| Household socioeconomic status | High | 36.7% (542) | 1 | 1 | ||
| Average | 46.8% (685) | 1.32 (1.12–1.57) | 0.002 | 1.40 (1.12–1.75) | < 0.001 | |
| Low | 46.8% (697) | 1.33 (1.10–1.61) | 1.41 (1.17–1.72) | |||
| Household net access | No | 40.4% (989) | 1 | |||
| Yes | 47.2% (935) | 1.23 (1.08–1.39) | 0.002 | |||
|
| ||||||
| Gender | Female | 41.2% (928) | 1 | |||
| Male | 45.7% (996) | 1.18 (1.05–1.34) | 0.007 | |||
| Ethnic group | Other | 39.4% (408) | 1 | |||
| Fon | 44.7% (1,516) | 1.17 (0.95–1.45) | 0.13 | |||
| Participant age | > 15 years | 31.2% (765) | 1 | 1 | ||
| 10–15 years | 67.9% (410) | 5.15 (4.23–6.28) | 4.96 (4.01–6.13) | |||
| 5–10 years | 69.1% (440) | 5.43 (4.47–6.61) | < 0.001 | 5.52 (4.48–6.81) | < 0.001 | |
| ≤ 5 years | 42.1% (309) | 1.66 (1.39–1.98) | 1.68 (1.39–2.03) | |||
| Duration usage of LLIN | ≤ 1 year | 37.4% (116) | 1 | |||
| 2 years | 43.7% (1,139) | 1.41 (1.07–1.84) | ||||
| 3 years | 47.2% (408) | 1.58 (1.17–2.13) | 0.01 | |||
| > 3 years | 37.0% (110) | 1.15 (0.78–1.70) | ||||
| Net usage the previous week | All nights | 43.2% (1,552) | 1 | 1 | ||
| Most of nights | 43.3% (154) | 1.18 (0.91–1.54) | 0.04 | 1.01 (0.76–1.36) | 0.02 | |
| Few nights | 51.5% (67) | 1.60 (1.09–2.35) | 1.83 (1.19–2.83) | |||
| Net conditions | Good | 38.4% (289) | 1 | 1 | ||
| Average | 42.9% (732) | 1.23 (0.99–1.53) | 0.002 | 1.23 (0.97–1.55) | 0.04 | |
| Poor | 46.1% (705) | 1.48 (1.17–1.85) | 1.37 (1.07–1.74) | |||
aOR = adjusted odds ratio; LLIN = long-lasting insecticidal nets; OR = odds ratio.
Adjusted for within-cluster effect.
Adjusted for significant variables associated with malaria infection and within-cluster effect.
Figure 1.Comparison map of malaria prevalence and vector density within the 60 study clusters. This figure appears in color at www.ajtmh.org.