MalariaWorld journal最新文献

Background: To determine the prevalence and clinical profile of malaria among febrile HIV-infected patients followed up in three HIV clinics in Ivory Coast.

Materials and methods: A cross-sectional multicentre study was conducted between 2009 and 2010 in the Pneumology Department of Cocody Teaching Hospital in Abidjan, Medical Esperance Centre and the Regional Hospital in San-Pedro. Patients of all ages presenting with fever (rectal or axillary temperature >37,5°C) or a medical history of fever within 72 hrs prior to consultation were included. Parasitological diagnostic methods used were microscopy by blood smear (BS) for search malaria parasite and parasite density. Haemoglobin levels were assessed to assess anaemia.

Results: Over the study period, 530 people living with HIV consulted for fever. The 476 patients included were predominantly female (n=280, 59%), with a median age of 34 (range 3-74 yrs), a mean of 38 ± 8.3 (SD) yrs, infected with HIV-1 (n=409, 86%), on antiretroviral therapy (n=376, 79%), and cotrimoxazole prophylaxis (n=381, 80%). Only 73 (15%) patients were using LLINs. Malaria prevalence was 10% (n=47). Plasmodium falciparum was the only species identified with a mean density of 15 900 trophozoites/μl. Malaria was more common among patients with a CD4 count of <200/mm³ (p<0.001) neither on cotrimoxazole prophylaxis (p<0.001) nor on antiretroviral therapy (ART) (p<0.001). Uncomplicated malaria accounted for 32 (68%) of the cases. The signs of severe malaria (n=15, 32%,) were dominated by severe anaemia (n= 12, 25.5%).

Conclusion: Our study revealed that malaria prevalence appears to be low in HIV clinics for people living with HIV on HAART and cotrimoxazole prophylaxis. Uncomplicated malaria is predominant when consultation is early. Signs of severe malaria were dominated by severe anaemia.

Background: Long Lasting Impregnated mosquito Net (LLIN) use is effective against malaria in endemic tropical areas. However, its utilisation remains limited. Among the most common clinical signs of malaria is fever and many studies have reported the existence of different local ways of handling fever; amongst which uncontrolled used of antimalarial drugs. We investigated LLINs use and its impact on fever outcomes and the various therapeutic measures used to deal with fever episodes.

Materials and methods: Data was extracted from a cross sectional descriptive and analytic study performed between January and April 2014 in Mifi health district. Data was collected in households through a face to face interview with standard household questionnaires, treated and analysed using Epi Info statistical software version 3.5.3.

Results: A total of 317 participants were interviewed with average age 33.2 years (SD = 10.8). Female respondents were predominant (85.2%; n=270). Most participants attended secondary education (53.6%; n= 170). Married marital status was most represented (58.1%; n= 185). 75.4% (n=239) of households owned at least 1 LLIN against an estimated average district coverage of 1 LLIN for 3.3 persons. Average bednet usage for households owning at least 1 LLIN was 57.9%. Utilisation of LLINs in households reduced fever episodes by 5.3%, (p=0.36). To handle fever episodes, road side medicines represented priority therapeutic itinerary for most of our respondents (95.0%; n=301).

Conclusions: Although LLINs are effective in reducing fever episodes, their utilisation remains low. Self-medication to treat fever seems to be prominent. There is a need to optimise communication for behavioural change strategies to promote consistent LLIN use and anti-malarial therapy, assisted by qualified health personnel.

Background: Tawau was the epicentre of malaria infections in the 1970-1990's, when industrialisation swept across the state of Sabah, Malaysia. Since then, effective public health intervention, mainly the Malaria Elimination Programme, introduced in 1998, has seen the disease shrivel down into its final elimination phase. Here we retrospectively analyse the case of a 63 year old male with multiple comorbidities who had no exposure to localities with high risk of infection- thus raising the question regarding the means of transmission.

Materials and methods: Multiple interviews and an entomological survey were conducted to elucidate the possible mechanism of infection in this patient.

Results: Findings point to locally-transmitted malaria, likely introduced by a patient from an endemic region in Tawau. Transmission via this route is rare, and has never before been reported in our setting.

Conclusions: This rare case highlights the need for constant vigilance in malaria control and elimination, especially when the target of country-wide elimination is close.

Background: Deployment of sound diagnostic tests remains a crucial component of malaria management, prevention and control in Africa. We undertook a comparative assessment of sensitivity, specificity and efficiency of three popular brands of rapid diagnostic tests (RDT) available in Nigerian market alongside with traditional microscopy.

Materials and methods: 525 samples of patients that presented with acute uncomplicated malaria through clinical diagnosis were evaluated with the various tests. Total WBC count and haematocrit were also measured.

Results: Of the 525 samples, 300 (57.1%) were found positive by Giemsa microscopy. SD Bioline had a positivity rate of 49.5% (260/525), while the positivity rate for Acon was significantly lower (38.1%; 200/525) and Paracheck (28.6%; 150/525). The sensitivity, specificity and efficiency of the three RDTs were: SD Bioline (86.3%, 99.6%, 92%); Paracheck (50%, 97.7%, 70.4%) and Acon (66.7%, 100%, 80.9%), respectively. Pre-teens aged 6-12 yrs had the highest mean malaria parasite densities with 6,631.26 at p< 0.01. The dominant malaria species was Plasmodium falciparum with 280 (93.3%) cases. Co-infections of P. falciparum/vivax (15; 5.0%) and P. falciparum/malariae (5; 1.7%) were detected and confirmed with microscopy. Haematocrit values correlated inversely with parasite density (r = -0.744; p< 0.01).

Conclusions: Microscopy still remains the reference standard for malaria diagnosis in limited resource settings in endemic areas. In furtherance to this, there is need for consistent monitoring of RDT product quality as part of the distribution process to end-users across Nigeria.

Background: There is dearth of information on perinatally acquired malaria, as well as its burden in Nigeria. We determined the prevalence of pregnancy-associated malaria and its burden among parturients in Abeokuta, Ogun State.

Materials and methods: Blood films from 211 parturients were prepared, stained with 10% Giemsa and examined using microscopy. Relevant demographic information was recorded from study participants. Chi-square tests were used to analyse data using SPSS version 20.0.

Results: Prevalence of maternal peripheral, placenta and cord blood parasitaemia were 40.8%, 19.0% and 5.7% respectively, and these were significantly correlated with age and gravidity. Prevalence of maternal anaemia was 45.0%, and was significantly associated with malaria infection. The occurrence of Low Birth Weight (LBW) was 10%. Maternal, placental and cord infections with malaria were associated with LBW, with the highest percentage of LBW occurring in babies with high placental malaria parasite density. Preterm delivery and stillbirth were significantly associated with placenta and cord malaria.

Conclusions: Impact of malaria on the mother and the newborns, notably anaemia and LBW, solicits the need for promoting use of available malaria prevention during pregnancy. These include LLINs and IPTp.

Background: The spread of artemisinin resistant malaria from SE Asia to the rest of the world remains a threat that will only be ended by eliminating malaria from the region. Novel control approaches are required to mitigate this threat. Spatial repellents (SR) are one such approach. We therefore conducted a multiple cross-over experiment from April 2013 - April 2014, in which all houses in one of two villages in Mondolkiri Province, Cambodia were alternately supplied with an emanator of the spatial repellent metofluthrin per 30 m³ of protected area to cover all potential peridomestic areas where people might spend their time before sleeping. Emanators were replaced every month for a three-month period.

Material and methods: Mosquito densities were simultaneously monitored in each village for two weeks every month using six CDC light-traps/night run from 18.00 to 07.00 hrs inside bedrooms and malaria prevalence, seroconversion and gSG6 protein rates assessed from prevalence surveys. After emanators were installed in the first village they were installed in the second village for a further three-month period and following that were again used in the initial village for a further three months. Surveys were undertaken before the initial installation of the emanators and at each cross-over point.

Results: Anopheles dirus densities were highest in houses closest to the forest. Transmission rates were low even before the application of the emanators. Perhaps due to the low levels of malaria transmission in Mondolkiri no significant relationships were found in Plasmodium cases or seroconversion rates between villages, surveys or by intervention. Adult males, who might spend more time unprotected in the forest at night, appeared to be at greater risk of becoming infected with P. falciparum malaria as compared to women or young children.

Conclusion: At the malaria transmission levels present in Mondolkiri the metofluthrin emanators evaluated had no observable effect on malaria prevalence. This may be due to confounding by low prevalence rates.

Hemozoin is generally considered a waste deposit that is formed for the sole purpose of detoxification of free heme that results from the digestion of hemoglobin by Plasmodium parasites. However, several observations of parasite multiplication, both in vertebrate and invertebrate hosts are suggestive of a wider, but overlooked, metabolic role for this product. The presence of clinical peripheral blood samples of P. falciparum with high parasitemia containing only hemozoin-deficient (non-pigmented) asexual forms has been repeatedly confirmed. Such samples stand in contrast with other samples that contain mostly pigmented circulating trophozoites and gametocytes, indicating that pigment accumulation is a prominent feature of gametocytogenesis. The restricted size, i.e. below detection by light microscopy, of hemozoin in asexual merozoites and ringforms of P. falciparum implies its continuous turnover, supporting a role in metabolism. The prominent interaction of hemozoin with several antimalarial drugs, the involvement of proteins in hemozoin formation, and the finding of plasmodial genes coding for a heme-oxygenase-like protein argue for a wider and more active role for hemozoin in the parasite's metabolism. The observed association of hemozoin with crystalloids during ookinete development is consistent with a useful function to it during parasite multiplication in the invertebrate host. Finally, alternative mechanisms, other than hemozoin formation, provide substitute or additional routes for heme detoxification.

Background: We report cases of gestational and congenital malaria with twin prematurity, low birth weight and bacterial co-infection. Congenital malaria is often misdiagnosed for lack of specific symptoms and a general lack of awareness of this presumably uncommon condition, and its diagnosis and prognosis become even more complex in the event of bacterial co-infections.

Case presentation: A 35-weeks pregnant woman with sickle-cell disease and a history of spontaneous abortions was admitted at Vanga Hospital in DR Congo. She had fever (38.9°C) and microscopy-confirmed P. falciparum malaria and was put on 80/480 mg artemether-lumefantrine. She soon went into active labour, during which both twins developed acute foetal distress and were promptly delivered by C-section. The twins were underweight, and both had P. falciparum malaria at birth and were given 20 mg quinine twice daily. Both developed fever on the third day; a bacterial infection was suspected and 200 mg ceftriaxone was added to their treatment. Fever in both twins quickly resolved, and one twin totally recovered within 2 days of antibiotic treatment. The other twin developed acute respiratory distress and hypoxia and died.

Discussion: This is a case of gestational and congenital malaria with prematurity, low birth weight and bacterial co-infection, but the patients were initially only treated for malaria based on their malaria-positive blood smears at birth.

Conclusions: In malaria-endemic areas, babies should be screened for congenital malaria. Even with a confirmed malaria infection in the new-born, it is important consider the possibility of bacterial co-infections.

Background: In Nigeria, decline in the sensitivity of Plasmodium falciparum to Artemisinin Combination Therapy (ACT) has prompted the unofficial use of chloroquine (CQ) for self-medication. This study was designed to determine the prevalence and distribution of CQ resistant/susceptible alleles of CQ resistance transporter (Pfcrt) and P. falciparum multidrug resistance gene 1 (Pfmdr1) in view of the possible re-introduction of CQ for malaria treatment.

Materials and methods: Four hundred and sixty six (466) P. falciparum positive samples were randomly collected from five states of northwest Nigeria. The samples were amplified using RT- PCR at codon 76 for Pfcrt and codon 86 for Pfmdr1. Data was analysed using chi-square, odds ratios and paired t-tests.

Results: Drug susceptible alleles (N86) were most prevalent in the study population (47.9%; 223/466), followed by the drug resistance alleles 86Y (28.3%; 132/466), followed by the drug susceptible alleles K76 (17.4%; 81/466), the resistant alleles 76T (12.4%; 58/466) and finally the mixed infection mutation K76T (3.6%; 17/466). Differences between the distributions of the Pfmdr1 and Pfcrt alleles were significant (P<0.05). There were significant differences (P<0.05) between N86 and 86Y alleles, but no significant differences between K76 and 76T alleles, including the prevalence of the various alleles across the different age groups.

Conclusion: The results of this study suggest the possibility of (re)introducing CQ for malaria treatment in north-western Nigeria and provide insight in the genetic background of P. falciparum in the study area.

Background: Antimalarial drug-resistant Plasmodium falciparum strains have been a major obstacle to the global efforts of controlling and eliminating malaria. The hope of reintroducing chloroquine for the treatment of uncomplicated malaria follows recent reports on decreases in the prevalence of chloroquine-resistant P. falciparum in several countries and recently, its total disappearance in Malawi and Zambia. In Nigeria, the discontinued use of chloroquine for malaria treatment was officially announced in 2005. A few available reports have shown a persistent high prevalence of the major biomarker of chloroquine resistance in southwest Nigeria. However, information on its prevalence in rural and urban areas is scanty. We investigated possible factors associated with the prevalence of a biomarker for chloroquine-resistance in Ogun State, southwest Nigeria.

Materials and methods: Parasite DNA was extracted from dried blood spots collected by finger-prick in malaria symptomatic and asymptomatic subjects attending the urban-based State General Hospital and a rural-based Primary Health Centre. A structured questionnaire was used to collect data on malaria/fever treatment history. Nested Polymerase Chain Reaction (PCR) followed by Restriction Fragment Length Polymorphisms (RFLP) analysis was used to detect mutations in the P. falciparum chloroquine resistance transporter (Pfcrt).

Results: Of the 243 participants recruited for this study, 56 were found to harbour P. falciparum parasites, of which 62.5% (35/56) showed symptoms of malaria. Prevalence of P. falciparum chloroquine-resistant strains (Pfcrt K76T) was 69.6%. The prevalence of Pfcrt K76T recorded in the rural area (91.7%) was significantly higher (P<0.05) than that in the urban area (53.1%). There was no correlation between prevalence of chloroquine-resistant strains and malaria symptoms in the rural area. However, prevalence of chloroquine-resistant strains was significantly higher in malaria-symptomatic subjects from the urban area.

Conclusions: Drug-resistant P. falciparum strains recorded in the rural area were associated with self-medication and patronage of drug vendors who continue to sell chloroquine. These findings present the importance of continuous surveillance of biomarkers indicating drug resistance especially now that antimalarial drug resistance is a threat to malaria eradication.