Entomological aspects and the role of human behaviour in malaria transmission in a highland region of the Republic of Yemen.

BACKGROUND: The Republic of Yemen has the highest incidence of malaria in the Arabian Peninsula, yet little is known of its vectors or transmission dynamics. METHODS: A 24-month study of the vectors and related epidemiological aspects of malaria transmission was conducted in two villages in the Taiz region in 2004-2005. RESULTS: Cross-sectional blood film surveys recorded an overall malaria infection rate of 15.3 % (250/1638), with highest rates exceeding 30 % in one village in May and December 2005. With one exception, Plasmodium malariae, all infections were P. falciparum. Seven Anopheles species were identified among 3407 anophelines collected indoors using light traps (LT) and pyrethrum knockdown catches (PKD): Anopheles arabiensis (86.9 %), An. sergentii (9 %), An. azaniae, An. dthali, An. pretoriensis, An. coustani and An. algeriensis. Sequences for the standard barcode region of the mitochondrial COI gene confirmed the presence of two morphological forms of An. azaniae, the typical form and a previously unrecognized form not immediately identifiable as An. azaniae. ELISA detected Plasmodium sporozoites in 0.9 % of 2921 An. arabiensis (23 P. falciparum, two P. vivax) confirming this species as the primary malaria vector in Yemen. Plasmodium falciparum sporozoites were detected in An. sergentii (2/295) and a single female of An. algeriensis, incriminating both species as malaria vectors for the first time in Yemen. A vector in both wet and dry seasons, An. arabiensis was predominantly anthropophilic (human blood index = 0.86) with an entomological inoculation rate of 1.58 infective bites/person/year. Anopheles sergentii fed on cattle (67.3 %) and humans (48.3; 20.7 % mixed both species), but only 14.7 % were found in PKDs, indicating predominantly exophilic behaviour. A GIS analysis of geographic and socio-economic parameters revealed that An. arabiensis were significantly higher (P < 0.001) in houses with televisions, most likely due to the popular evening habit of viewing television collectively in houses with open doors and windows. CONCLUSIONS: The predominantly indoor human biting vectors recorded in this study could be targeted effectively with LLINs, indoor residual spraying and/or insecticide-treated window/door curtains reinforced by education to instil a perception that effective and affordable malaria prevention is achievable.

Feasibility and acceptability of ACT for the community case management of malaria in urban settings in five African sites.

BACKGROUND: The community case management of malaria (CCMm) is now an established route for distribution of artemisinin-based combination therapy (ACT) in rural areas, but the feasibility and acceptability of the approach through community medicine distributors (CMD) in urban areas has not been explored. It is estimated that in 15 years time 50% of the African population will live in urban areas and transmission of the malaria parasite occurs in these densely populated areas. METHODS: Pre- and post-implementation studies were conducted in five African cities: Ghana, Burkina Faso, Ethiopia and Malawi. CMDs were trained to educate caregivers, diagnose and treat malaria cases in < 5-year olds with ACT. Household surveys, focus group discussions and in-depth interviews were used to evaluate impact. RESULTS: Qualitative findings: In all sites, interviews revealed that caregivers' knowledge of malaria signs and symptoms improved after the intervention. Preference for CMDs as preferred providers for malaria increased in all sites.Quantitative findings: 9001 children with an episode of fever were treated by 199 CMDs in the five study sites. Results from the CHWs registers show that of these, 6974 were treated with an ACT and 6933 (99%) were prescribed the correct dose for their age. Fifty-four percent of the 3,025 children for which information about the promptness of treatment was available were treated within 24 hours from the onset of symptoms.From the household survey 3700 children were identified who had an episode of fever during the preceding two weeks. 1480 (40%) of them sought treatment from a CMD and 1213 of them (82%) had received an ACT. Of these, 1123 (92.6%) were administered the ACT for the correct number of doses and days; 773 of the 1118 (69.1%) children for which information about the promptness of treatment was available were treated within 24 hours from onset of symptoms, and 768 (68.7%) were treated promptly and correctly. CONCLUSIONS: The concept of CCMm in an urban environment was positive, and caregivers were generally satisfied with the services. Quality of services delivered by CMDs and adherence by caregivers are similar to those seen in rural CCMm settings. The proportion of cases seen by CMDs, however, tended to be lower than was generally seen in rural CCMm. Urban CCMm is feasible, but it struggles against other sources of established healthcare providers. Innovation is required by everyone to make it viable.

Household cost of malaria overdiagnosis in rural Mozambique.

BACKGROUND: It is estimated that over 70% of patients with suspected malaria in sub-Saharan Africa, diagnose and manage their illness at home without referral to a formal health clinic. Of those patients who do attend a formal health clinic, malaria overdiagnosis rates are estimated to range between 30-70%. METHODS: This paper details an observational cohort study documenting the number and cost of repeat consultations as a result of malaria overdiagnosis at two health care providers in a rural district of Mozambique. 535 adults and children with a clinical diagnosis of malaria were enrolled and followed over a 21 day period to assess treatment regimen, symptoms, number and cost of repeat visits to health providers in patients misdiagnosed with malaria compared to those with confirmed malaria (determined by positive bloodfilm reading). RESULTS: Diagnosis based solely on clinical symptoms overdiagnosed 23% of children (<16y) and 31% of adults with malaria. Symptoms persisted (p = 0.023) and new ones developed (p < 0.001) in more adults than children in the three weeks following initial presentation. Adults overdiagnosed with malaria had more repeat visits (67% v 46%, p = 0.01-0.06) compared to those with true malaria. There was no difference in costs between patients correctly or incorrectly diagnosed with malaria. Median costs over three weeks were $0.28 for those who had one visit and $0.76 for > or = 3 visits and were proportionally highest among the poorest (p < 0.001) CONCLUSION: Overdiagnosis of malaria results in a greater number of healthcare visits and associated cost for adult patients. Additionally, it is clear that the poorest individuals pay significantly more proportionally for their healthcare making it imperative that the treatment they receive is correct in order to prevent wastage of limited economic resources. Thus, investment in accurate malaria diagnosis and appropriate management at primary level is critical for improving health outcomes and reducing poverty.

Evaluation of a syndromic surveillance for the early detection of outbreaks among military personnel in a tropical country.

BACKGROUND: To evaluate a new military syndromic surveillance system (2SE FAG) set up in French Guiana. METHODS: The evaluation was made using the current framework published by the Centers for Disease Control and Prevention, Atlanta, USA. Two groups of system stakeholders, for data input and data analysis, were interviewed using semi-structured questionnaires to assess timeliness, data quality, acceptability, usefulness, stability, portability and flexibility of the system. Validity was assessed by comparing the syndromic system with the routine traditional weekly surveillance system. RESULTS: Qualitative data showed a degree of poor acceptability among people who have to enter data. Timeliness analysis showed excellent case processing time, hindered by delays in case reporting. Analysis of stability indicated a high level of technical problems. System flexibility was found to be high. Quantitative data analysis of validity indicated better agreement between syndromic and traditional surveillance when reporting on dengue fever cases as opposed to other diseases. CONCLUSIONS: The sophisticated technical design of 2SE FAG has resulted in a system which is able to carry out its role as an early warning system. Efforts must be concentrated on increasing its acceptance and use by people who have to enter data and decreasing the occurrence of the frequency of technical problems.

Malaria and anaemia among children in two communities of Kumasi, Ghana: a cross-sectional survey.

BACKGROUND: A survey in Kumasi, Ghana found a marked Plasmodium falciparum prevalence difference between two neighbouring communities (Moshie Zongo and Manhyia). The primary objective of this follow-up study was to determine whether this parasite rate difference was consistent over time. Secondary objectives were to compare prevalences of clinical malaria, anaemia, intestinal parasite infections, and malnutrition between these communities; and to identify potential risk factors for P. falciparum infection and anaemia. METHODS: A cross-sectional house-to-house survey of P. falciparum parasitaemia, clinical malaria, anaemia, anthropometric indices, and intestinal helminths was conducted in April-May 2005. Data collection included child and household demographics, mosquito avoidance practices, distance to nearest health facility, child's travel history, symptoms, and anti-malarial use. Risk factors for P. falciparum and anaemia (Hb < 11 g/dl) were identified using generalized linear mixed models. RESULTS: In total, 296 children were tested from 184 households. Prevalences of P. falciparum, clinical malaria, anaemia, and stunting were significantly higher in Moshie Zongo (37.8%, 16.9%, 66.2% and 21.1%, respectively) compared to Manhyia (12.8%, 3.4%, 34.5% and 7.4%). Of 197 children tested for helminths, four were positive for Dicrocoelium dendriticum. Population attributable risks (PAR%) of anaemia were 16.5% (P. falciparum) and 7.6% (malnutrition). Risk factors for P. falciparum infection were older age, rural travel, and lower socioeconomic status. Risk factors for anaemia were P. falciparum infection, Moshie Zongo residence, male sex, and younger age. CONCLUSION: Heterogeneities in malariometric indices between neighbouring Kumasi communities are consistent over time. The low helminth prevalence, and the twofold higher PAR% of anaemia attributable to P. falciparum infection compared to malnutrition, indicate the importance of malaria as a cause of anaemia in this urban population.

Malaria misdiagnosis: effects on the poor and vulnerable.

CONTEXT: Effective and affordable treatment is recommended for all cases of malaria within 24 h of the onset of illness. Most cases of "malaria" (ie, fever) are self-diagnosed and most treatments, and deaths, occur at home. The most ethical and cost-effective policy is to ensure that newer drug combinations are only used for true cases of malaria. Although it is cost effective to improve the accuracy of malaria diagnosis, simple, accurate, and inexpensive methods are not widely available, particularly in poor communities where they are most needed. STARTING POINT: In a recent study in Uganda, Karin Kallander and colleagues emphasise the difficulty in making a presumptive diagnosis of malaria, and highlight the urgent need for improved diagnostic tools that can be used at community and primary-care level, especially in poorer populations (Acta Trop 2004; 90: 211-14). WHERE NEXT? Health systems need strengthening at referral and community level, so that rapid accurate diagnosis and effective treatment is available for those who are least able to withstand the consequences of illness. Indirect evidence strongly suggests that misdiagnosis of malaria contributes to a vicious cycle of increasing ill-health and deepening poverty. Much better direct evidence is needed about why and how misdiagnosis affects the poor and vulnerable.

Malaria and urbanization in sub-Saharan Africa.

There are already 40 cities in Africa with over 1 million inhabitants and the United Nations Environmental Programme estimates that by 2025 over 800 million people will live in urban areas. Recognizing that malaria control can improve the health of the vulnerable and remove a major obstacle to their economic development, the Malaria Knowledge Programme of the Liverpool School of Tropical Medicine and the Systemwide Initiative on Malaria and Agriculture convened a multi-sectoral technical consultation on urban malaria in Pretoria, South Africa from 2nd to 4th December, 2004. The aim of the meeting was to identify strategies for the assessment and control of urban malaria. This commentary reflects the discussions held during the meeting and aims to inform researchers and policy makers of the potential for containing and reversing the emerging problem of urban malaria.

Combined ultrasound and serologic screening for hepatic alveolar echinococcosis in central China.

Alveolar echinococcosis (AE), caused by Echinococcus multilocularis, is a zoonotic helminthic disease that can mimic malignancy. In the 1970s, foci of the disease were found in central China. The aim of the present study was to estimate the prevalence of AE in humans in 2 districts of south Gansu Province, China, by use of ultrasound and Echinococcus serology. After answering an epidemiological questionnaire, 2,482 volunteers from 28 villages underwent ultrasound. Serology via enzyme-linked immunosorbent assay for antibody activity was performed on whole blood collected on filter paper in all subjects; on serum from subjects with an abnormal ultrasound image; and on randomly chosen subjects that either had no lesions or had atypical lesions. At least one (25.3%) abnormal ultrasound image was observed in 630 of the subjects screened. A typical lesion of progressive AE was found in 84 subjects (3.4%). Serologies were positive in 77 (96%) of 80 of patients who had lesions typical of progressive AE. Ultrasound is useful for screening for AE in endemic regions.

Strategies to improve adherence to recommended chloroquine treatment regimes: a quasi-experiment in the context of integrated primary health care delivery in Ghana.

This paper presents the results of an intervention study carried out as part of the activities of a District Health Management Team responsible for integrated primary health care delivery in a rural district in Ghana. The aim was to test the impact of a combination of improved information provision to patients and drug labeling on adherence to recommended anti-malarial treatment regimens focusing on oral chloroquine, for the outpatient management of acute uncomplicated malaria. The study had a quasi-experimental pre-test post-test control group design with partly random allocation by clinic. The results show that the intervention resulted in an improved flow of information to clients prescribed chloroquine, and better labeling of drugs for the home treatment of acute clinical episodes of malaria in the intervention area. Improvements in adherence occurred in all clinics. However, improvements in adherence were most marked in the clinic that was worst performing at the start of the intervention. Implications of the results for improving adherence to chloroquine therapy on an outpatient basis are discussed.

Integrated community case management of fever in children under five using rapid diagnostic tests and respiratory rate counting: a multi-country cluster randomized trial.

Evidence on the impact of using diagnostic tests in community case management of febrile children is limited. This effectiveness trial conducted in Burkina Faso, Ghana, and Uganda, compared a diagnostic and treatment package for malaria and pneumonia with presumptive treatment with anti-malarial drugs; artemisinin combination therapy (ACT). We enrolled 4,216 febrile children between 4 and 59 months of age in 2009-2010. Compliance with the malaria rapid diagnostic test (RDT) results was high in the intervention arm across the three countries, with only 4.9% (17 of 344) of RDT-negative children prescribed an ACT. Antibiotic overuse was more common: 0.9% (4 of 446) in Uganda, 38.5% (114 of 296) in Burkina Faso, and 44.6% (197 of 442) in Ghana. Fever clearance was high in both intervention and control arms at both Day 3 (97.8% versus 96.9%, P = 0.17) and Day 7 (99.2% versus 98.8%, P = 0.17). The use of diagnostic tests limits overuse of ACTs. Its impact on antibiotic overuse and on fever clearance is uncertain.

Improved mapping strategy to better inform policy on the control of schistosomiasis and soil-transmitted helminthiasis in Sierra Leone.

BACKGROUND: Schistosomiasis and soil-transmitted helminthiasis (STH) are endemic in Sierra Leone confirmed by national mapping in 2008. To better inform planning of preventive chemotherapy strategy, another survey was conducted before mass drug administration (MDA) in seven districts according to the mapping results or local knowledge. Fifty-nine chiefdoms and one school in every chiefdom were selected. Thirty school children aged 9-14 years from each school (total: 1760) were examined by parasitological methods for infection with Schistosoma mansoni and STHs. RESULTS: The overall prevalence of S. mansoni was 40.2% (95% confidence interval (CI): 37.9-42.5%), particularly in Kailahun (63.3%), Kenema (46.7%), Koinadugu (41.9%) and Kono (71.7%). The results demonstrated the focal distribution of S. mansoni in Bo, Tonkolili and Bombali districts with prevalence ranging from 0.0-63.3%, 3.3-90.0% and 0.0-67.9% respectively. The arithmetic mean intensity of S. mansoni infection was 95.4 epg (95% CI: 61.4-129.5 epg), Heavy mean intensity of infection was found in Kailahun (120.2 epg), Kenema (104.5 epg), Koinadugu (112.3 epg) and Kono (250.3 epg). Heavy or moderate infection with S. mansoni occurred in 20.7% of children examined. Hookworm prevalence was moderate: 31.2% (95% CI: 29.1-33.4%), but high in Bo (50.0%) and Tonkolili (56.7%). Hookworm intensity of infection was light with a mean epg of 53.0 (95% CI: 38.4-67.7 epg). Prevalence and intensity of Ascaris lumbricoides (1.5%, 17.8 epg) and Trichuris trichiura (2.5%, 20.3 epg) was low. CONCLUSIONS: The prediction by previous spatial analysis that S. mansoni was highly endemic across north-eastern Sierra Leone was confirmed with a significant proportion of children heavily or moderately infected. The distribution of S. mansoni in Bo, Tonkolili and Bombali districts ranged widely, highlighting the importance of considering the nature of focal transmission in national mapping exercises. These results were used to refine the MDA for schistosomiasis control to chiefdom implementation units rather than the entire district in these 3 districts. The survey demonstrated that sufficient number of survey sites for schistosomiasis mapping in each district should be used to provide a better national planning of MDA activities, and that it is affordable with the contributions from all parties involved and national resources mobilized.

Cohort trial reveals community impact of insecticide-treated nets on malariometric indices in urban Ghana.

The efficacy of insecticide-treated nets (ITNs) in prevention of malaria and anaemia has been shown in rural settings, but their impact in urban settings is unknown. We carried out an ITN intervention in two communities in urban Accra, Ghana, where local malaria transmission is known to occur. There was evidence for a mass or community effect, despite ITN use by fewer than 35% of households. Children living within 300 m of a household with an ITN had higher haemoglobin concentrations (0.5g/dl higher, P=0.011) and less anaemia (odds ratio 2.21, 95% CI 1.08-4.52, P=0.031 at month 6), than children living more than 300 m away from a household with an ITN, although malaria parasitaemias were similar. With urban populations growing rapidly across Africa, this study shows that ITNs will be an effective tool to assist African countries to achieve their Millennium Development Goals in urban settings. [Registered trial number ISRCTN42261314; http://www.controlled-trials.com/ISRCTN42261314].

Urban malaria and anaemia in children: a cross-sectional survey in two cities of Ghana.

OBJECTIVE: To describe the epidemiology of urban malaria, an emerging problem in sub-Saharan Africa. METHOD: Cross-sectional surveys of communities in Accra and Kumasi, Ghana, determining risk factors for malaria infection and anaemia in children aged 6-60 months. RESULTS: Malaria prevalence rates ranged from 2% to 33% between urban communities. 47.1% of children were anaemic (Hb<11.0 g/dl). Factors associated with malaria prevalence were low socio-economic status, age and anaemia. The attributable risks of anaemia and severe anaemia (Hb<8.0 g/dl) caused by malaria were 5% and 23% respectively. CONCLUSIONS: Malaria in urban areas displayed a heterogeneity and complexity that differed from the rural environment, which has important implications for malaria control. Marked intra-city variation indicates the importance of targeting specific areas or districts. The most vulnerable group, the urban poor, should be prioritized when designing control measures. This would require careful assessment of the malaria risk pattern in any city to guide an integrated control program.

Progress report on the control of schistosoma mansoni transmission on St. Lucia using molluscicides

Precontrol studies and the strategy for using molluscicides to control Sehistosoma mansoni transmission on St. Lucia were reported in earlier papers: this paper summarises the results obtained during the first 21/2 years of control programme. An initial intensive treatment with the molluscicide Bayluscide was given in September/October 1970 to all habitats in the study area, Cul-de-Sac Valley, from which the intermediate host of Schistosoma mansoni (the freshwater snail Biomphalaria glabrata) had been recovered in the previous five years. A surveillance - treatment programme was evolved in which all the previously infested areas were searched on a two to three-weekly cycle and focal applications of the molluscicide were given to any snail colonies discovered. Quantitative snail sampling in untreated valleys showed the snail populations to behaving normally with large numbers of infected snails appearing in streams during try seasons. Similar samples at index sites in Cul-de-Sac valley yeilded no snails after January 1971, and no cercariae were detected in selected sites. The surveillance results showed about 80 percent of the marshes and banana drains to be entirely clear of snails or to yield them less than four times a year; snail control in the remaining 20 percent was less satisfactory, mainly due to dense vegetation which hampered both searching and spraying. No snails have been recovered from streams - the most dangerous transmission sites - since mid 1971, of all the snails recovered throughout this period was infected. Human data for the first 15 months of the programme showed a drop in the incidence of new S. mansoni infections of nearly 50 percent over the previous year compared with a rise of nearly 100 percent in similar, untreated areas. In view of the snail findings, it is hoped that the mollusciciding programme will have a greater impact on transmission during the second half of this programme (AU)

Schistosoma mansoni control in Cul de Sac Valley, Saint Lucia. 1. A two-year focal surveillance-mollusciciding programme for the control of Biomphalaria glabrata

An area-wide mollusciciding campaign in Cul de Sac valley, St. Lucia reduced incidence of Schistosoma mansoni from 22 percent to 4.3 percent between 1970 and 1975. Following this, a two-year focal surveillance-mollusciciding programme was introduced. Sites of potential transmission of S. mansoni were identified and routinely searched for Biomphalaria glabrata. If found, the site was treated with clonitrralide 25 percent emulsifiable concentrate. Two chemotherapy campaigns supplemented the snail control programme. As a result of the combined measures, incidence of the infection dropped from 4.3 percent to 1.0 percent and from 2.2 percent to 0.6 percent in areas originally of high and low transmission respectively. The cost of protecting the 7,000 population was US $20,362: of these costs, labour absorbed 68 percent, transport 24 percent, equipment 4 percent and molluscicide 4 percent. The cost per person per year protected was US $1.45 which compares favourably with the $3.24 of the previous scheme. Although effective and relatively cheap, this programme was still dependent on a high standard of supervision for maximum benefit. (AU)

Routine focal mollusciciding after chemotherapy to control Schistosoma mansoni in Cul de Sac valley, St. Lucia

Concluding results of a ten year schistosomiasis control programme in Cul de Sac valley, St. Lucia, are described. After an area wide mollusciciding campaign (1970-1975), and a surveillance/treatment programme supplemented with selective population chemotherapy in 1975 and 1976, prevelence rates of Schistosoma mansoni were reduced to low levels. To prevent a resurgence of transmission a cost effective routine focal mollusciciding programme, suitable for public health implementation was evaluated from 1977 to 1981. Streams and main collector drains in banana fields, considered to be potential S. mansoni transmission sites, were treated every four weeks with Bayluscide 6076 emulsifiable concentrate (Clonitralide). Snail populations were effectively controlled in the treated areas but large numbers were present where no treatment was given. Only 0.06 percent of sentinel snails became infected. Prevalence of infection in the human population remained low (over-all 5 percent) and intensity of infection at a level not normally associated with schistosomal disease. Since control started ten years earlier the level of potential contamination has fallen by 92 percent in high transmisssion areas. The four year programme cost US$12,909, of which 54 percent was for molluscicide, 27 percent for labour and 19 percent for transport, equipment and sundries. The average annual cost per head of population was US$0.46

Laboratory and field trials of a slow-release copper molluscicide in St. Lucia

Tests of a slow-release molluscicide containing 50 percent copper sulfate were undertaken in laboratory and field situations in St. Lucia. In laboratory trials, a granule form of the molluscicide produced 100 percent mortality of Biomphalaria glabrata down to 4 mg.liter active ingredient (a.i), while the pellet form produced 100 percent mortality down to 8 mg/liter a.i. In field trials, a dose of 100 mg/liter a.i. in granule form caused mortality of B. glabrata in banana drains but had no effect on B. glabrata populations in a marsh habitat. In both habitats, the dose of 100mg/liter produced mortality of other molluscan fauna which caused changes in the molluscan diversity indices. This failure in field trials may have been due to dilution of copper levels caused by flooding and also by uptake of copper by mud and algae (AU)

Evaluation of an experimental mollusciciding programme to control Schistosoma mansoni transmission in St Lucia

The size and number of colonies of Biomphalaria glabrata were reduced after four years of a surveillance/treatment snail control programme using an emulsifiable concentrate of niclosamide (25 percent active ingredient). Surveys among the human population showed that the incidence of new Schistosoma mansoni infections in 0-10 year-old children fell from 22 percent to 4.3 percent, while in a comparison area the incidence remained at 20 percent. With the reduced transmission over four years, the prevalence of infection in a cohort of children examined in 1971 and 1975 fell from 34 percent to 23 percent. The fall in prevalence and intensity of infection led to a reduction of 66 percent in the index of potential contamination, which was reflected in a reduced rate of infection among sentinel snails and representative samples of B. glabrata collected during surveillance searchs. The overall annual cost of the programme was US $3.24 per capita (AU)