Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.2.7.5 (AOR)
 1,763 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malaria infection is thought to be relatively infrequent in infants less than 90 days of age in sub-Saharan Africa. In a rural area of Malawi with intense malaria transmission, we examined the occurrence of malaria infection during infancy and risk factors for parasitemia in the first three months of life in the cohort of infants delivered to women in the Mangochi Malaria Research Project. Among 3,915 liveborn singleton infants, 3,432 (87.7%) were seen at least once during infancy (first 12 months of life); of these, malaria blood smear results were available on 2,649 (77.2%). Overall, in a cross-sectional analysis, 23.3% of infants at three months of age were infected with Plasmodium falciparum; this proportion increased to more than 30% during the high transmission season. By the age of 10 months, 60-80% of the infants were infected, depending on the season. Geometric mean parasite density increased each month after two months of age and plateaued at seven months of age. In a life-table analysis, the median time to acquisition of a positive smear was 199 days. Factors independently associated with smear positivity at < 4 months of age included visit during high transmission season (adjusted odds ratio [AOR] = 4.1), maternal smear positivity at the same visit (AOR = 3.5), history of infant fever in the previous two weeks (AOR = 2.8), birth during the rainy season (AOR = 1.7), low socioeconomic status (AOR = 1.6), and low maternal education (AOR = 1.5). The specificity of a recent fever history for malaria infection in early infancy was high (> 70%). Intervention strategies to reduce the risk of early infant infection need to be targeted toward mothers of infants at high risk.
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PMID:Malaria infection in infancy in rural Malawi. 870 41

The factors affecting the development of patent Plasmodium falciparum gametocytemia were assessed in 5,682 patients entered prospectively into a series of antimalarial drug trials conducted in an area of low and seasonal transmission on the western border of Thailand. Of the 4,565 patients with admission thick smear assessments, 110 (2.4%) had gametocytemia. During the follow-up period 170 (3%) of all patients developed patent gametocytemia, which in 89% had developed by day 14 following treatment. In a multiple logistic regression model five factors were found to be independent risk factors at presentation for the development or persistence of gametocytemia during follow up; patent gametocytemia on admission (adjusted odds ratio [AOR] = 7.8, 95% confidence interval [CI] = 3.7-16, P < 0.001), anemia (hematocrit <30%) (AOR = 3.9, 95% CI = 2.3-6.5, P < 0.001), no coincident P. vivax malaria (AOR = 3.5, 95% CI = 1.04-11.5, P < 0.04), presentation with a recrudescent infection (AOR = 2.3, 95% CI = 1.3-4.1, P < 0.004), and a history of illness longer than two days (AOR = 3.3, 95% CI = 1.7-6.6, P < 0.001). Patients whose infections responded slowly to treatment or recrudesced subsequently were also more likely to carry gametocytes than those who responded rapidly or were cured (relative risks = 1.9, 95% CI = 1.3-2.7 and 2.8, 95% CI = 2.0-4.0, respectively; P < 0.001). These data provide further evidence of important epidemiologic interactions between P. falciparum and P. vivax, and drug resistance and transmission potential.
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PMID:Risk factors for gametocyte carriage in uncomplicated falciparum malaria. 1040 36

We conducted a case record study comparing liver tests abnormalities in 20 malaria-related acute renal failure cases without cerebral malaria, 52 cerebral malaria cases without other organ impairment, 189 cases of nonsevere malaria associated with a high parasite burden, and 131 cases of mild Plasmodiumfalciparum malaria. Jaundice and hepatomegaly were significantly associated with renal failure (adjusted odds ratio [AOR], 3.3, 95% confidence interval [CI], 1.3-8.6, P = 0.01; and AOR, 1.7 95% CI, 1.13-2.4, P = 0.01) but not with cerebral malaria (AOR, 1, 95% CI, 0.5-2, P = 0.8; and AOR, 1.08, 95% CI, 0.8-1.8, P = 0.5). Patients with acute renal failure were significantly older and had increased liver abnormalities compared with other groups. Although an increase in the proportion of mature schizonts over ring forms was significantly associated with cerebral malaria, it did not seem to have affected acute renal failure. These results suggested that cytoadherence was not the main determinant for renal failure and that jaundice itself may have potentiated the effects of hypovolemia.
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PMID:Association of hepatomegaly and jaundice with acute renal failure but not with cerebral malaria in severe falciparum malaria in Thailand. 1179 81

Following studies showing an association between helminth infections and protection from cerebral malaria, we compared 22 patients with malaria-associated acute renal failure with 157 patients with moderately severe malaria. Helminths were associated with protection from renal failure (adjusted odds ratio [AOR], 0.16 [0.03-0.85], P = 0.03). Helminth-infected controls were less likely to have jaundice (AOR, 0.39 [0.16-0.96], P = 0.04) or to have peripheral mature schizonts (AOR, 0.2 [0.07-0.62], P = 0.005) than controls without helminths. This suggested that preexisting helminth infections may have been protective by influencing sequestration and obstructive jaundice, 2 possible determinants of acute tubular necrosis.
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PMID:Helminth infections are associated with protection from malaria-related acute renal failure and jaundice in Thailand. 1179 82

Malaria control strategies are more likely to be successful if groups at high risk can be accurately predicted. Given that mosquitoes have an obligate aquatic phase we were interested in determining how vector larval abundance relates to the spatial distribution of human malaria infection. We examined the relationship between malaria parasite prevalence and distance from vector larval habitat, and vector larval abundance and distance from human habitation, in separate studies in rural, low-endemic areas of the Philippines. Parasite prevalence among symptomatic patients was significantly higher among those living in proximity (< or = 50 m) to potential larval habitats of the major vector, Anopheles flavirostris (adjusted odds ratio [AOR] = 2.64, P = 0.02 and AOR = 3.43, P = 0.04). A larval survey of A. flavirostris revealed a higher density of early and late instars near human habitation (adjusted P < 0.05). The results suggest that larvae are associated with human habitation, thereby reinforcing malaria risk in people living close to larval habitats. This has implications for understanding the interaction between vectors, hosts, and parasites, and the potential for success of localized malaria control measures.
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PMID:Host-dependent Anopheles flavirostris larval distribution reinforces the risk of malaria near water. 1522 42

A study was conducted in order to determine whether children that slept under untreated bednets were protected against both malaria infection and clinical disease compared with children not sleeping under bednets. The study was conducted in Kilifi District, Kenya, during the malaria season (June-August, 2000) and involved 416 children aged < or = 10 years. Data collected from a cross-sectional survey showed evidence of protection against malaria infection among children sleeping under untreated bednets in good condition compared with those not using nets (adjusted odds ratio [AOR] = 0.4, 95% CI 0.22-0.72, P = 0.002). There was no evidence of a protective effect against infection when comparing those that used untreated bednets that were worn and those not using nets (AOR = 0.75, 95% CI 0.34-1.63, P = 0.47). When these same children were followed-up during the malaria season, there was evidence of a lower rate of clinical malaria among those that used untreated nets in good condition (adjusted incidence rate ratio = 0.65, 95% CI 0.45-0.94, P = 0.022), while the rate of clinical malaria among those that used untreated bednets that were worn was similar to that of those that did not use bednets. In the face of persistent failure of communities to take up net retreatment, there is hope that untreated nets will offer some protection against malaria infection and disease compared with not using nets at all.
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PMID:The effects of untreated bednets on malaria infection and morbidity on the Kenyan coast. 1525 58

The risk factors associated with gametocytaemia at presentation and after treatment with different antimalarial drug regimens were evaluated in 767 children enrolled prospectively in 5 antimalarial drug trials between July 1996 and December 2002 in a hyperendemic area of southwestern Nigeria. The children were assigned to one of 6 treatment groups: chloroquine (CQ) only; pyrimethamine-sulfadoxine (PS) only; amodiaquine (AQ) only; CQ combined with chlorpheniramine (CQCP); or PS combined with CQ (CQPS) or AQ (AQPS). At enrolment, 115 (15%) of 767 children were gametocyte carriers. During follow-up, 15.6% of all patients (i.e. 120 patients) developed patent gametocytaemia, which in 85% (102 patients) had developed by day 7 following treatment. In a multiple regression model, 4 factors were found to be independent risk factors for the presence of gametocytaemia at enrolment: male gender (adjusted odds ratio [AOR] = 0.55, 95% confidence interval [CI] 0.36-0.83, P=0.005), absence of fever (AOR = 1.61, 95% CI 1.05-2.5, P=0.03), duration of illness >3 days (AOR=1.57, 95% CI 1.0-2.4, P=0.047), and asexual parasite densities less than 5000/microl (AOR=0.42, 95% CI 0.24-0.73, P=0.002). The presence of patent gametocytaemia at enrolment (AOR=0.04, 95% CI 0.02-0.07, P<0.001) and recrudescence of asexual parasites within 14 days were associated with the presence of gametocytaemia 7 or 14 days after enrolment (AOR=0.5, 95% CI 0.3-0.8, P=0.007). Delay in the time taken to clear the initial parasitaemia (>2 days) was associated with increased risk of subsequent gametocyte carriage. These findings may have implications for malaria control efforts in sub-Saharan Africa where control of the disease depends almost entirely on chemotherapy.
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PMID:Risk factors for gametocyte carriage in uncomplicated falciparum malaria in children. 1547 Oct 1

To study the risk factors for Plasmodium vivax gametocyte carriage, the presence or absence of gametocytes was determined in 2,125 patients with P. vivax malaria participating in clinical trials at the Hospital for Tropical Diseases in Bangkok, Thailand. Stepwise logistic regression models were used to determine which variables were significantly related to gametocyte carriage. On admission, 615 patients (29%) had detectable gametocytes (before treatment). After treatment had started, an additional 245 patients (11%) developed patent gametocytemia. The variables retained by multivariate analysis were highest observed temperature (adjusted odds ratio [AOR] per degrees C increase = 0.82, 95% confidence interval [CI] = 0.71-0.94, P = 0.006), asexual parasitemia > 9,200/muL (AOR = 2.8, 95% CI = 1.9-4.2, P < 0.0001), erythrocyte counts (AOR = 0.8/million/muL increase, 95% CI = 0.67-0.95, P = 0.01), monocyte percentage (AOR = 0.93 per % increase, 95% CI = 0.89-0.96, P < 0.0001), lymphocyte percentage (AOR = 0.98 per % increase, 95% CI = 0.97-0.99, P = 0.006), albumin (AOR = 0.67 per 10 g/mL increase, 95% CI = 0.5-0.9, P = 0.007), and anion gap (AOR = 1.1 per unit increase, 95% CI = 1.02-1.14, P = 0.009). The possible significance of these observations is discussed.
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PMID:Risk factors for Plasmodium vivax gametocyte carriage in Thailand. 1564 56

Kenya established intermittent preventive treatment (IPT) with sulfadoxine-pyrimethamine (SP) for malaria in pregnancy as national policy in 1998. We assessed the coverage of IPT among women who had recently delivered in a rural area of western Kenya with perennial malaria transmission and high coverage with insecticide treated nets (ITNs) through a cross-sectional, community-based survey in December 2002. Antenatal clinic (ANC) attendance was high (89.9% of the 635 participating women); 77.5% of attendees visited an ANC before the third trimester and 91.9% made more than one visit. Delivery of SP by the ANC was reported by 19.1% of all women but only 6.8% reported receiving more than one dose. Given the high rate of use of ANC services, if SP were given at each visit after the first trimester, the potential coverage of IPT (two doses of SP) would be 80.3% in this study population. ITNs were used by 82.4% of women during pregnancy, and almost all mothers (98.5%) who slept under an ITN shared the nets with their newborns after delivery. Women who thought malaria in pregnancy caused foetal problems were more likely to have used an ITN (adjusted odds ratio [AOR] 1.6, 95% confidence interval [CI] 1.0-2.4), and to have visited ANC more than once (AOR 2.4, 95% CI 1.2-4.7) compared to women who thought malaria in pregnancy was either not a problem or caused problems for the mother only. These findings illustrate the need for improved IPT coverage in this rural area. Identification and removal of the barriers to provision of IPT during ANC visits can help to increase coverage. In this area of Kenya, health messages stressing that foetal complications of malaria in pregnancy may occur in the absence of maternal illness may improve the demand for IPT.
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PMID:Use of intermittent preventive treatment for malaria in pregnancy in a rural area of western Kenya with high coverage of insecticide-treated bed nets. 1626 38

The prevalence of pyrimethamine-sulfadoxine (PS)-resistant Plasmodium falciparum malaria has been increasing in sub-Saharan Africa or other parts of the world in the last one or two decades. The factors that identify children at risk of treatment failure after being given PS were evaluated in 291 children with acute, symptomatic, uncomplicated, P. falciparum malaria. The children took part in four antimalarial drug trials between July 1996 and July 2004 in a hyperendemic area of southwestern Nigeria. Following treatment, 64 (22%) of 291 children failed treatment by day 7 or 14. In a multivariate analysis, an age < or = 1.5 years (AOR=2.9, 95% CI 1.3-6.4, P = 0.009) and presence of fever (AOR = 3.3, 95% CI 1.28-7.14, P = 0.01) were independent predictors of the failure of treatment with PS at presentation. Following treatment, delay in parasite clearance >3 days (AOR = 2.56, CI 1.19-5.56, P = 0.016) was an independent predictor of the failure of treatment with PS. In addition, compared with the children who had no fever then, children with fever three or more days after starting treatment were more likely to be treatment failures. These findings may have implications for malaria control efforts in some sub-Saharan African countries where treatment of malaria disease depends almost entirely on PS monotherapy, and for programmes employing PS or PS-based combination therapy.
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PMID:Predictors of the failure of treatment with pyrimethamine-sulfadoxine in children with uncomplicated falciparum malaria. 1651 78


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