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Background
Objective
Methods
Results
Discussion
Assessing the Risk of Self-diagnosed Malaria in Urban
Informal Settlements
Yazoumé YéElizabeth Kimani
John KebasoFrederick Mugisha
Conclusion
INDEPTH Network AGM 2007, September 3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Malaria Endemicity in Kenya
• In Kenya, malaria is the leading cause of outpatient attendance in 6/8 provinces
• Level of malaria transmission varies across the country
• Different malaria epidemiological zones namely:
endemic zone, epidemic prone zone low risk zone.
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Malaria in Nairobi
• Nairobi, is classified as a low risk area
• High altitude (1700m) => cold temperatures limit transmission
• Urban habitat is less suitable for An. gambiae s.s. and An. Funestus
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
History of Malaria Cases in Nairobi
• 1926: Presence in Nairobi of An. gambiae and An. Funestus
• 1929: A school survey showed 2.5% parasites prevalence
0
200
400
600
800
1000
1200
1930s 1940s 1950s 1960s
Rep
orte
d ca
ses
of m
alar
ia
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Low Prevalence of Malaria in Nairobi
Pf prevalence at sites across the city in 1982 (Rapuoda & Achola, 1984)
0% 2% 4% 6% 8% 10% 12% 14%
Mwimuto
Embakasi
Kangemi
Dandora/Umoja
Kaloleni
Makadara
South B
Dagoretti
Makongeni
Pf prevalence
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Malaria Diagnosis in Nairobi
• Malaria is a common diagnosis among out-patients in the city
• Overuse of anti-malaria drug
• With introduction of ACT accurate diagnosis is needed
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Questions
• What is the level of self-diagnosed malaria in the community?
• Does the population from informal settlements perceive malaria as one of their key morbidities?Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
To explore the risk of perceived malaria and associated factors in two Nairobi informal settlements
Background
Objective
Methods
Results
Discussion
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Study Population
• Household survey May-August 2004
• 7288 individuals from DSS database
• Population of interest = 1394 individuals (reported at least one illness )
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objectives
Methods
Results
Discussion
Morbidity Survey
• Self report of maximum of three illnesses and associated symptoms
• Recall period: Past 15 days
• Proxy respondents for participants <14 years
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objectives
Methods
Results
Discussion
Statistical Analysis
• Outcome: Reported malaria (Y/N)
• Explanatory variables: Slum of residence, sex, age, ethnicity, symptom score
• Multivariate Logistic regression mode
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Computation of Symptom Scores
Tiredness
Loss of appetite
Abdominal pain
Diarrhoea
Fever
Convulsions
Headache
Vomiting
Joint pain
Selected symptoms malaria:
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objectives
Methods
Results
Discussion
Computation of Symptom Scores, cont
• Score= Fever + other symptoms
• Score=0, none of these symptoms
• Score=1, only fever was reported
• Score=2, fever+ 1 symptom
• Etc
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Factors n %
Ethnicity
Kikuyu 367 26.3
Kamba 311 22.3
Luha 199 14.3
Luo 305 21.9
Other 212 15.2
Symptoms
Score 0 413 29.6
Score 1 139 10.0
Score 2 291 20.9
Score 3 290 20.8
Score 4 168 12.1
Score 5+ 93 6.7
Factors n %
N 1394 100
Slums
Korogocho 818 58.7
Viwandani 576 41.3
Sex
Female 654 46.9
Male 739 53.0
Age group (years)
<5 343 24.6
5-14 235 16.9
15-24 214 15.4
25-39 367 26.3
>40 235 16.9
Study Population Characteristics
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Top Five Illnesses
416392
320
165
36 35 30
0
50
100
150
200
250
300
350
400
450
Nu
mb
er o
f C
ases
Other (160illnesses)
Malaria Common cold Don't know Typhoid Pneumonia Asthma Illnesses
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objective
Methods
Results
Discussion
Factors cases %
Ethnicity, x2, p<0.001
Kikuyu 83 22.6
Kamba 101 32.5
Luha 63 31.7
Luo 108 35.4
Other 37 17.5
Symptoms, x2, p<0.001
Score 0 24 5.8
Score 1 15 10.8
Score 2 101 34.7
Score 3 125 43.1
Score 4 76 45.2
Score 5+ 51 54.8
Factors cases %
N 392 28.1
Slums, x2, p=0.008
Korogocho 208 34.1
Viwandani 184 46.9
Sex, x2, p=0.250
Female 174 26.6
Male 218 29.5
Age group (yrs), x2, p<0.001
<5 81 23.6
5-14 50 21.3
15-24 60 28.0
25-39 136 37.1
>40 65 27.7
Distribution of Self-diagnosed Malaria
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Background
Objectives
Methods
Results
Discussion
Factors OR 95% CI
Ethnicity
Kikuyu 1
Kamba 1.5 [1.1 - 2.2]
Luha 2.2 [1.4 - 3.4]
Luo 2.1 [1.5 - 3.1]
Symptoms
Score 0 1
Score 1 2.1 [1.1 - 4.3]
Score 2 9.4 [5.8 - 15.5]
Score 3 13.6 [8.4 - 22.1]
Score 4 14.9 [8.8 - 25.3]
Score 5+ 23.7 [13.0 - 43.2]
Risk associated with Self-diagnosed Malaria
Factors OR 95 %CI
Slums
Korogocho 1
Viwandani 1.6 [1.1 - 2.3]
Sex
Female 1
Male 1.1 [0.9 - 1.5]
Age group (yrs)
<5 1
5-14 1.0 [0.7 - 1.6]
15-24 1.3 [0.9 - 2.0]
25-39 2.1 [1.4 – 3.0]
>40 1.3 [0.9 - 2.0]
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
• High level of self-diagnosed-malaria
• Expected high use of anti-malarial drugs
• Risk of development of drug resistance
• Wastage of scarce resources
Background
Objective
Methods
Results
Discussion
Discussion
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
• Risk factors suggest imported malaria
• High risk among age group 25-40 yrs
• High risk among Luo’s and Luyha from high risk areas
• High risk in Viwandani where there is high mobility
Background
Objective
Methods
Results
Discussion
Imported Malaria?
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
• Locally acquired malaria cannot be ruled out
• Significant proportion of the so-called stable population had reported malaria
• Nairobi is not a malaria free zone though the transmission may be low
Background
Objective
Methods
Results
Discussion
Locally Acquired Infection?
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
• Self reported approach for assessing malaria?
• However, very few (5.8%) reported malaria without fever
• ↑ number of symptoms was associated with ↑ risk of perceived malaria
• Fever was the basis of reporting malaria
Background
Objective
Methods
Results
Discussion
Reliability of Self-diagnosed
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
• Malaria is perceived as a problem by the community of the informal settlements
• Whether misdiagnosis or imported, there is a cause for concern for National control programs
• Need for a more comprehensive assessment of malaria epidemiology
Background
Objective
Methods
Results
Discussion
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
Key Messages
• Parasite prevalence surveys• Data on fever could be routinely
collected• History of travelling should be
collected
Background
Objective
Methods
Results
Discussion
Conclusion
INDEPTH Network
AGM 2007, September
3rd-7th, 2007
How can DSS help?
Thank you for your attention!!!
Yazoumé Yé, Elizabeth Kimani-Murage, John Kebaso and Frederick Mugisha. Assessing the risk of self-diagnosed malaria in urban informal settlements of Nairobi using self-reported morbidity survey. Malaria Journal 2007, 6:71
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