Showing papers in "Transactions of The Royal Society of Tropical Medicine and Hygiene in 2009"
TL;DR: The current state of the art in relation to diagnostic methods for detecting the infection, the morbidity caused by the infection and the recommended treatment are provided and the gaps in knowledge and future research needs related to this infection are pointed to.
Abstract: Soil-transmitted helminths of the genus Strongyloides (S. fuelleborni and the more prevalent S. stercoralis) are currently believed to infect an estimated 30-100 million people worldwide. The health consequences of S. stercoralis infections range from asymptomatic light infections to chronic symptomatic strongyloidiasis. Uncontrolled multiplication of the parasite (hyperinfection) and potentially life-threatening dissemination of larvae to all internal organs is found among individuals with compromised immune system functions. This paper provides an overview of the current state of the art in relation to diagnostic methods for detecting the infection, the morbidity caused by the infection and the recommended treatment. It further discusses some of the reasons why this infection is so neglected and the consequence of this for the estimated global prevalence. The paper finally points to the gaps in our knowledge and future research needs related to this infection. As Strongyloides infections have the potential to develop into severe disease in certain population subgroups, untreated infections could cause serious problems in the community. Therefore, we need to carefully investigate this parasite in order to develop and implement effective control programmes.
476 citations
TL;DR: The question is asked, are these diseases emerging because of climate change or do other factors play an equal or even more important role in their emergence?
Abstract: While some sceptics remain unconvinced that global climate change is a reality, there is no doubt that during the past 50 years or so, patterns of emerging arbovirus diseases have changed significantly. Can this be attributed to climate change? Climate is a major factor in determining: (1) the geographic and temporal distribution of arthropods; (2) characteristics of arthropod life cycles; (3) dispersal patterns of associated arboviruses; (4) the evolution of arboviruses; and (5) the efficiency with which they are transmitted from arthropods to vertebrate hosts. Thus, under the influence of increasing temperatures and rainfall through warming of the oceans, and alteration of the natural cycles that stabilise climate, one is inevitably drawn to the conclusion that arboviruses will continue to emerge in new regions. For example, we cannot ignore the unexpected but successful establishment of chikungunya fever in northern Italy, the sudden appearance of West Nile virus in North America, the increasing frequency of Rift Valley fever epidemics in the Arabian Peninsula, and very recently, the emergence of Bluetongue virus in northern Europe. In this brief review we ask the question, are these diseases emerging because of climate change or do other factors play an equal or even more important role in their emergence?
423 citations
TL;DR: This paper, drawing on Médecins Sans Frontières' experience of scaling-up antiretroviral treatment in three sub-Saharan African countries and supplemented by a review of the literature, highlights the main opportunities and challenges posed by task shifting and proposes specific actions to tackle the challenges.
Abstract: Sub-Saharan Africa is facing a crisis in human health resources due to a critical shortage of health workers. The shortage is compounded by a high burden of infectious diseases; emigration of trained professionals; difficult working conditions and low motivation. In particular, the burden of HIV/AIDS has led to the concept of task shifting being increasingly promoted as a way of rapidly expanding human resource capacity. This refers to the delegation of medical and health service responsibilities from higher to lower cadres of health staff, in some cases non-professionals. This paper, drawing on Medecins Sans Frontieres' experience of scaling-up antiretroviral treatment in three sub-Saharan African countries (Malawi, South Africa and Lesotho) and supplemented by a review of the literature, highlights the main opportunities and challenges posed by task shifting and proposes specific actions to tackle the challenges. The opportunities include: increasing access to life-saving treatment; improving the workforce skills mix and health-system efficiency; enhancing the role of the community; cost advantages and reducing attrition and international 'brain drain'. The challenges include: maintaining quality and safety; addressing professional and institutional resistance; sustaining motivation and performance and preventing deaths of health workers from HIV/AIDS. Task shifting should not undermine the primary objective of improving patient benefits and public health outcomes.
387 citations
TL;DR: A real-time PCR method targeting the small subunit of the rRNA gene was developed for the detection of Strongyloides stercoralis DNA in faecal samples, including an internal control to detect inhibition of the amplification process, and achieved 100% specificity and high sensitivity.
Abstract: A real-time PCR method targeting the small subunit of the rRNA gene was developed for the detection of Strongyloides stercoralis DNA in faecal samples, including an internal control to detect inhibition of the amplification process. The assay was performed on a range of well-defined control samples (n = 145), known positive faecal samples (n = 38) and faecal samples from a region in northern Ghana where S. stercoralis infections are highly endemic (n = 212), and achieved 100% specificity and high sensitivity. The use of this assay could facilitate monitoring the prevalence and intensity of S. stercoralis infections during helminth intervention programs. Moreover, the use of this assay in diagnostic laboratories could make the introduction of molecular diagnostics feasible in the routine diagnosis of S. stercoralis infections, with a two-fold increase in the detection rate as compared with the commonly used Baermann sedimentation method.
262 citations
TL;DR: The co-occurrence of both resistance mechanisms in a population of An.
Abstract: Pyrethroid insecticide resistance in Anopheles gambiae sensu stricto is a major concern to malaria vector control programmes. Resistance is mainly due to target-site insensitivity arising from a single point mutation, often referred to as knockdown resistance (kdr). Metabolic-based resistance mechanisms have also been implicated in pyrethroid resistance in East Africa and are currently being investigated in West Africa. Here we report the co-occurrence of both resistance mechanisms in a population of An. gambiae s.s. from Nigeria. Bioassay, synergist and biochemical analysis carried out on resistant and susceptible strains of An. gambiae s.s. from the same geographical area revealed >50% of the West African kdr mutation in the resistant mosquitoes but <3% in the susceptible mosquitoes. Resistant mosquitoes synergized using pyperonyl butoxide before permethrin exposure showed a significant increase in mortality compared with the non-synergized. Biochemical assays showed an increased level of monooxygenase but not glutathione-S-transferase or esterase activities in the resistant mosquitoes. Microarray analysis using the An. gambiae detox-chip for expression of detoxifying genes showed five over-expressed genes in the resistant strain when compared with the susceptible one. Two of these, CPLC8 and CPLC#, are cuticular genes not implicated in pyrethroid metabolism in An. gambiae s.s, and could constitute a novel set of candidate genes that warrant further investigation.
164 citations
TL;DR: There was an overlap of genotypes in the same ecotope, raising the possibility of transmission through the oral route and the need for early therapeutic intervention for better patient management in the Brazilian Amazon.
Abstract: An outbreak of Chagas disease occurred in Mazagao, Amapa, Brazilian Amazon in 1996. Seventeen of 26 inhabitants presented symptoms compatible with acute Chagas disease and were submitted to parasitological and serological tests. All 17 were positive in at least one parasitological test and 11 were also IgM or IgG anti-Trypanosoma cruzi positive. The nine asymptomatic patients were negative for parasites and one was positive for IgG anti-T. cruzi. Sixty-eight triatomines were captured (66 Rhodnius pictipes; two Panstrongylus geniculatus); 45 were infected with T. cruzi (43 R. pictipes; two P. geniculatus). Thirteen trypanosomatid strains were isolated: eight from humans and five from R. pictipes. Four were genotyped as T. cruzi I (two from humans; two from R. pictipes), seven as T. cruzi Z3 (six from humans; one from R. pictipes) and two as T. cruzi Z3 and T. rangeli (from R. pictipes). Treatment started for all patients leading to a decrease in parasitaemia in 16 during the follow-up period (6 months, 1, 5 and 7 years). All were serologically negative 7 years post-treatment. There was an overlap of genotypes in the same ecotope, raising the possibility of transmission through the oral route and the need for early therapeutic intervention for better patient management in the Brazilian Amazon.
142 citations
TL;DR: The high sensitivity of FLOTAC holds promise for patient management, monitoring soil-transmitted helminth transmission and endpoint(s) of control at the population level, while Kato-Katz revealed considerably higher infection intensities thanFLOTAC.
Abstract: Accurate diagnostic tools are pivotal for patient management and surveillance of helminth control programmes, particularly in the current era of preventive chemotherapy. Three consecutive stool samples were obtained from 279 schoolchildren from Zanzibar, an island where anthelminthic drugs have been administered on a large scale for more than a decade. All stool samples were examined with the Kato-Katz method. Additionally, one sample per child was preserved in sodium acetate-acetic acid-formalin solution, and examined with the FLOTAC technique. Considering the pooled results of both methods as diagnostic 'gold' standard, the observed prevalences of Trichuris trichiura, hookworm and Ascaris lumbricoides were 63.4, 35.8 and 22.9%, respectively. The sensitivity of examining a single stool sample by FLOTAC for diagnosing T. trichiura, hookworm and A. lumbricoides was 88.7, 83.0 and 82.8%, respectively. Lower sensitivities were observed for Kato-Katz even after examining three stool samples: 71.8, 46.0 and 70.3%, respectively. Kato-Katz revealed considerably higher infection intensities than FLOTAC. The kappa agreement between a single FLOTAC and triplicate Kato-Katz was 0.63 for diagnosing A. lumbricoides and 0.50 for T. trichiura, but only 0.30 for hookworm. The high sensitivity of FLOTAC holds promise for patient management, monitoring soil-transmitted helminth transmission and endpoint(s) of control at the population level.
141 citations
TL;DR: People living above 2000 m and people of all ages are still at significant risk of malaria infection, but significant protective factors were found: number of LLINs per household, living at higher altitude and household wealth.
Abstract: We assessed malaria infection in relation to age, altitude, rainfall, socio-economic factors and coverage of control measures in a representative sample of 11437 people in Amhara, Oromia and SNNP regions of Ethiopia in December 2006-January 2007. Surveys were conducted in 224 randomly selected clusters of 25 households (overall sample of 27884 people in 5708 households). In 11538 blood slides examined from alternate households (83% of those eligible), malaria prevalence in people of all ages was 4.1% (95% CI 3.4-4.9), with 56.5% of infections being Plasmodium falciparum. At least one mosquito net or one long-lasting insecticidal net (LLIN) was present in 37.0% (95% CI 31.1-43.3) and 19.6% (95% CI 15.5-24.5) of households, respectively. In multivariate analysis (n=11437; 82% of those eligible), significant protective factors were: number of LLINs per household (odds ratio [OR] (per additional net)=0.60; 95% CI 0.40-0.89), living at higher altitude (OR (per 100 m)=0.95; 95% CI 0.90-1.00) and household wealth (OR (per unit increase in asset index)=0.79; 95% CI 0.66-0.94). Malaria prevalence was positively associated with peak monthly rainfall in the year before the survey (OR (per additional 10 mm rain)=1.10; 95% CI 1.03-1.18). People living above 2000 m and people of all ages are still at significant risk of malaria infection.
134 citations
TL;DR: HIV prevalence is high in children with SAM in sub-Saharan Africa, and HIV-infected children are at significantly increased risk of mortality, and there is an urgent need to integrate HIV testing and treatment into care for children withSAM in regions of high HIV prevalence.
Abstract: This systematic review and meta-analysis explored HIV prevalence and mortality in children undergoing treatment for severe acute malnutrition (SAM) in sub-Saharan Africa. It included all studies reporting on HIV infection within a sample of children with SAM where HIV status was assessed using a blood test and SAM was defined using the WHO, Gomez, Wellcome or Waterlow definitions. Children from 17 studies were included in the analysis (n=4891), of whom 29.2% were HIV-infected. HIV-infected children were significantly more likely to die than HIV-uninfected children (30.4% vs. 8.4%; P<0.001; relative risk=2.81, 95% CI 2.04-3.87). HIV-negative children treated within community-based therapeutic care (CTC) programmes had lower mortality (4.3%) than those treated within an inpatient nutrition rehabilitation unit (NRU) (15.1%). There was no significant difference in mortality for HIV-infected children with SAM treated in the CTC (30.0%) or NRU (31.3%) settings. HIV prevalence is high in children with SAM in sub-Saharan Africa, and HIV-infected children are at significantly increased risk of mortality. There is an urgent need to integrate HIV testing and treatment into care for children with SAM in regions of high HIV prevalence.
134 citations
TL;DR: Major risk factors were found by bivariate and multivariate analysis to include eating raw or undercooked meat, unwashed raw vegetables or fruit, contact with cats, living in rural areas, and low educational standards.
Abstract: Infection with Toxoplasma gondii is common and usually asymptomatic, but it can have serious consequences in pregnant women if passed to the developing fetus. The aims of this study were to determine the prevalence of toxoplasmosis in pregnant women and to identify the possible risk factors associated with T. gondii infection in China. Of a sample of 235 pregnant women in Changchun, China, 25 (10.6%) were found by ELISA to be positive for IgG and none (0%) for IgM. Major risk factors were found by bivariate and multivariate analysis to include eating raw or undercooked meat, unwashed raw vegetables or fruit, contact with cats, living in rural areas, and low educational standards. In order to lower congenital infection, pregnant women need to be informed about the risk factors for toxoplasmosis.
131 citations
TL;DR: The rise and fall of clinically important forms of drug-resistant falciparum malaria is reviewed and how lessons learned from studying the evolution ofdrug-resistant malaria can be applied to efforts to prevent and deter resistance is considered.
Abstract: Molecular epidemiological investigations have uncovered the patterns of emergence and global spread of Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine. Malaria parasites highly resistant to chloroquine and pyrimethamine spread from Asian origins to Africa, at great cost to human health and life. If artemisinin-resistant falciparum malaria follows the same pattern, renewed efforts to eliminate and eradicate malaria will be gravely threatened. This paper, adapted from a talk given in honour of Professor Malcolm Molyneux in Liverpool in September 2008, reviews the rise and fall of clinically important forms of drug-resistant falciparum malaria and considers how lessons learned from studying the evolution of drug-resistant malaria can be applied to efforts to prevent and deter resistance.
TL;DR: Intestinal parasites should be looked for routinely in Indonesian HIV/AIDS patients with chronic diarrhoea and should be treated to reduce complications and the likelihood of transmission.
Abstract: We investigated the occurrence of intestinal parasites in Indonesian HIV/AIDS patients with chronic diarrhoea prior to administering antiretroviral therapy. The influence of age, CD4(+) cell count and season on parasite occurrence was also studied. In total, 318 unconcentrated stool samples were analysed using Lugol's iodine and modified acid fast staining to detect intestinal coccidia. Most samples (94.5%) were from males aged 21-40 years with CD4(+) counts < or = 50 cells/mm(3). Parasites were found in 84.3% of samples (single species infections, 71.4%; polyparasitism, 12.9%), with protozoan pathogens occurring most commonly. Cryptosporidium (4.9%), Cyclospora cayetanensis (4.5%) and Giardia duodenalis (1.9%) were the most frequent single infections, but Blastocystis hominis (72.4%) was the most commonly occurring protist. Cryptosporidium and C. cayetanensis occurred in 11.9% and 7.8% of all (single and mixed) infections. The most common co-infection was with B. hominis and Cryptosporidium (6.3%). Intestinal protozoan pathogens were detected more frequently in cases with CD4(+) counts < or = 200/mm(3). No seasonal influence was determined for Cryptosporidium, C. cayetanensis or B. hominis, but gross seasonal disturbances may have influenced our findings. Intestinal parasites should be looked for routinely in this group of individuals and should be treated to reduce complications and the likelihood of transmission.
TL;DR: The explicative model could contribute to developing a warning signal to reduce the impact of a presumed cholera epidemic in Zambia by estimating the association between the increase in number of cases and climatic factors.
Abstract: In this study, we aimed to describe the evolution of three cholera epidemics that occurred in Lusaka, Zambia, between 2003 and 2006 and to analyse the association between the increase in number of cases and climatic factors. A Poisson autoregressive model controlling for seasonality and trend was built to estimate the association between the increase in the weekly number of cases and weekly means of daily maximum temperature and rainfall. All epidemics showed a seasonal trend coinciding with the rainy season (November to March). A 1 degrees C rise in temperature 6 weeks before the onset of the outbreak explained 5.2% [relative risk (RR) 1.05, 95% CI 1.04-1.06] of the increase in the number of cholera cases (2003-2006). In addition, a 50 mm increase in rainfall 3 weeks before explained an increase of 2.5% (RR 1.02, 95% CI 1.01-1.04). The attributable risks were 4.9% for temperature and 2.4% for rainfall. If 6 weeks prior to the beginning of the rainy season an increase in temperature is observed followed by an increase in rainfall 3 weeks later, both exceeding expected levels, an increase in the number of cases of cholera within the following 3 weeks could be expected. Our explicative model could contribute to developing a warning signal to reduce the impact of a presumed cholera epidemic.
TL;DR: The association between DDT resistance and the presence of L1014S is consistent with a co-dominant effect, with heterozygous individuals showing an intermediate phenotype, and the distribution and prevalence of insecticide resistance and its association with target-site mutations in eastern Uganda is collected.
Abstract: Insecticide resistance in Anopheles gambiae threatens the success of malaria vector control programmes in sub-Saharan Africa. In order to manage insecticide resistance successfully, it is essential to assess continuously the target mosquito population. Here, we collected baseline information on the distribution and prevalence of insecticide resistance and its association with target-site mutations in eastern Uganda. Anopheles gambiae s.l. adults were raised from wild-caught larvae sampled from two ecologically distinct breeding sites and exposed to WHO discriminating concentrations of DDT, permethrin, deltamethrin, bendiocarb and malathion. Survival rates to DDT were as high as 85.4%, alongside significant resistance levels to permethrin (38.5%), reduced susceptibility to deltamethrin, but full susceptibility to bendiocarb and malathion. Using molecular diagnostics, susceptible and resistant specimens were further tested for the presence of knockdown resistance (kdr) and acetylcholinesterase 1 resistance (ace-1(R)) alleles. While ace-1(R) and kdrL1014F ('kdr west') alleles were absent, the kdr L1014S ('kdr east') allele was present in both populations. In A. gambiae s.s., L1014S was closely associated with DDT and, to a lesser degree, with permethrin resistance. Intriguingly, the association between DDT resistance and the presence of L1014S is consistent with a co-dominant effect, with heterozygous individuals showing an intermediate phenotype
TL;DR: Polytrematode infection is highly prevalent in Lao PDR and hence requires urgent attention.
Abstract: Food-borne trematodiasis is an emerging public health problem, including in Lao PDR. We investigated the diversity of intestinal helminthes and polyparasitism in patients with hepatobiliary or intestinal symptoms in hospital and community-based surveys. Stool samples from 232 individuals aged ≥15 years were examined by the Kato-Katz method (three samples) and a formalin ethyl-acetate concentration technique (one sample). Opisthorchis viverrini and minute intestinal flukes (MIF) were common, with prevalences of 86.2% and 62.9%, respectively. Hookworm was the predominant soil-transmitted helminth (65.9%). The prevalences of Taenia spp., Strongyloides stercoralis and Trichuris trichiura were 22.8%, 10.3% and 8.6%, respectively. Additionally, 97 individuals were purged; O. viverrini and Haplorchis taichui were found in 95 and 76 participants, respectively. Other trematodes included Phaneropsolus bonnei (22.7%), Prosthodendrium molenkampi (14.4%), Haplorchis pumilio (5.2%), Haplorchis yokogawai (3.1%) and Echinochasmus japonicus (3.1%). Co-infection with O. viverrini and MIFs was rampant (81.4%). Polytrematode infection is highly prevalent in Lao PDR and hence requires urgent attention.
TL;DR: As Malawi continues to extend the coverage (and equity) of ART, including in rural areas, attention is needed to reduce losses to follow-up at hospital level and reduce mortality at primary care level.
Abstract: We report on rates of patient retention and attrition in the context of scaling-up antiretroviral treatment (ART) within a district hospital and its primary health centres in rural Malawi. 'Retention' was defined as being alive and on ART or transferred out, whereas 'attrition' was defined as died, lost to follow-up or stopped treatment. A total of 4074 patients were followed-up for 1803 person-years: 2904 were at the hospital and 1170 at health centres. Approximately 85% of patients were retained in care, both at hospital and health centres, with a retention rate per 100 person-years of 185 and 211, respectively [adjusted hazard ratio (HR) 1.18, 95% CI 1.10-1.28, P=0.001). Attrition rates per 100 person-years were similar: 33 and 36, respectively (adjusted HR 1.17, 95% CI 0.97-1.4, P=0.1). At health centres the incidence of loss to follow-up was significantly lower than at the hospital (adjusted HR 0.24, P<0.001, risk reduction 77%), but the rate of reported deaths was higher at health centres (adjusted HR 2.2, 95% CI 1.76-2.72, P<0.001). As Malawi continues to extend the coverage (and equity) of ART, including in rural areas, attention is needed to reduce losses to follow-up at hospital level and reduce mortality at primary care level.
TL;DR: The results draw attention to the need for early HIV diagnosis, increased access to HAART services with earlier treatment initiation, and routine screening and aggressive management of opportunistic infections, particularly tuberculosis.
Abstract: A retrospective cohort study of mortality rates and potential predictors of death was conducted in public-sector patients initiating highly active antiretroviral therapy (HAART) between October 2005 and September 2007 in a rural, under-resourced region of South Africa. The aims were to determine the relative contribution of death to cohort exit and the causes and predictors of mortality among HAART initiators. A community outreach programme traced non-attenders. Patients categorised as dying at home underwent a verbal autopsy (by interviewing family members) and case-file review, and those dying in hospital a case-file review, to determine the probable cause of death. At 24 months 1131 (83.6%) patients were retained on treatment in the programme, 124 (9.2%) had died, 63 (4.7%) had transferred out, and 35 (2.6%) were lost to follow-up. The most common causes of death were tuberculosis (44.3%) and diarrhoeal diseases (24.5%). Death was the major reason for cohort exit. As experience is gained with rural HAART programmes mortality rates may decrease. These results draw attention to the need for early HIV diagnosis, increased access to HAART services with earlier treatment initiation, and routine screening and aggressive management of opportunistic infections, particularly tuberculosis.
TL;DR: The distribution of pyrethroid and DDT resistance and the L1014F knockdown resistance (kdr) mutation in Anopheles gambiae s.l. gambiae populations is reported on to have practical significance for malaria vector control programs.
Abstract: This study reports on the distribution of pyrethroid and DDT resistance and the L1014F knockdown resistance (kdr) mutation in Anopheles gambiae s.l. populations from 21 localities in three different climatic zones of Burkina Faso from August to October 2006. The susceptibility of these populations was assessed by bioassay using DDT (4%), permethrin (1%) and deltamethrin (0.05%). Anophelesgambiae were resistant to both permethrin and DDT in the Sudanian regions but were susceptible in the central and sahelian areas and susceptible to deltamethrin at all sites except Orodara, although mortality values in some populations were close to the resistance threshold. The kdr frequency varied from 0.4 to 0.97 in populations from the Sudanian region and was lower in populations from the Sudano-sahelian and sahelian areas (0.047 to 0.54). Compared to the last survey of kdr in An. gambiae populations conducted in 2000, the kdr frequency did not differ in the S form but had increased in the M form (0.6), with an extended distribution into the Sudano-sahelian region. The frequency of kdr was also found to have increased in An. arabiensis populations (0.28), where it was formerly reported in only a single specimen. These results have practical significance for malaria vector control programs.
TL;DR: The consensus that has emerged is that eradication of malaria, although theoretically possible, is not likely to be feasible within the medium term using existing control tools, but malaria elimination is a realistic short- to medium-term goal for an increasing number of countries that are already bringing malaria under control.
Abstract: Since the perceived failure of the Global Programme for Malaria Eradication in 1969, the eradication of malaria has not been considered a feasible goal. However, in October 2007 the goal of malaria eradication was resurrected by Melinda and Bill Gates, and this aspiration has subsequently been endorsed by the WHO and by the Roll Back Malaria Partnership. This change in direction of malaria control has provoked a vigorous debate within the malaria research and control communities as to whether resurrection of the goal of eradication at this point in time is helpful or likely to be counterproductive. The consensus that has emerged is that eradication of malaria, although theoretically possible, is not likely to be feasible within the medium term using existing control tools. However, malaria elimination (cessation of local transmission) is a realistic short- to medium-term goal for an increasing number of countries that are already bringing malaria under control.
TL;DR: In areas of low transmission, urinary schistosomiasis was greatly reduced, but, by contrast, other intervention strategies are needed to complement and synergise with chemotherapy in high transmission areas.
Abstract: As part of a 4-year control programme beginning in 2003 and entitled Piga Vita Kichocho, around 140 000 school-aged children on Unguja Island, Zanzibar were treated annually with a combination of praziquantel and albendazole. To provide information on the impact of this intervention, a subset of children, originating from 24 sentinel schools, were monitored in 2004, 2005 and 2006 using both parasitological and behavioural questionnaire methods. Overall, prevalence of urinary schistosomiasis fell by 52%, intensity by 55% and gross haematuria by 82%. There was a positive and statistically significant correlation between areas of elevated disease prevalence and areas of predicted high transmission based upon local occurrence of the permissive intermediate snail host. In areas of low transmission, urinary schistosomiasis was greatly reduced, but, by contrast, other intervention strategies are needed to complement and synergise with chemotherapy in high transmission areas. Whereas significant reductions were documented in the prevalence of both Trichuris trichiura and hookworm, prevalence of Ascaris lumbricoides significantly increased over the monitoring period. Through a detailed analysis of named child records, evidence of predisposition to helminth (re)infection and individual bias towards polyparasitism was detected, highlighting the often overlapping distribution of these parasites within the school-aged child.
TL;DR: The results of this epidemiological study indicate a high prevalence of leishmaniasis in rural areas of Shiraz and the Leishmania major strain was identified in the majority of cases.
Abstract: Summary Cutaneous leishmaniasis (CL) continues to be an increasing public health problem in Iran. Shiraz, a city in Fars Province in southwestern Iran, is one of the endemic foci of CL. However, there is no formal report of endemicity of CL in rural areas of Shiraz. To our knowledge, this is the first report of an epidemic of zoonotic CL in this area. The purpose of this study was to examine the epidemiological features of leishmaniasis in three villages in rural areas of Shiraz and to identify the causative species of leishmaniasis using nested PCR with clinical direct samples. The prevalence of infection among 1000 inhabitants of the three villages was 23.2%. Prevalences of ulcers and scars were 7 and 16.2%, respectively. The most infected age group was 0–9 years, with a rate of 14.2%. Children are more than twice as susceptible to the infection. In this study, the Leishmania major strain was identified in the majority of cases. The results of this epidemiological study indicate a high prevalence of leishmaniasis in rural areas of Shiraz.
TL;DR: The importance of considering strongyloidiasis in all patients on immunosuppressive drug therapy who present with gastrointestinal symptoms so that the patient can be appropriately investigated and promptly treated is highlighted.
Abstract: Strongyloides stercoralis, a nematode parasite, is endemic in tropical and subtropical regions. Infection usually remains asymptomatic, but in immunocompromised hosts hyperinfection and dissemination can occur, which has a high mortality. Early detection of S. stercoralis may alter the fatal course of infection. We present our experience of five patients with S. stercoralis hyperinfection diagnosed by endoscopic duodenal and jejunal biopsy in northern India. A predisposing factor was present in all patients in the form of corticosteroid intake, chronic liver disease and panhypogammaglobulinaemia. Common gastrointestinal symptoms were abdominal pain, diarrhoea, gastrointestinal bleeding, nausea, vomiting and weight loss with evidence of malabsorption. The initial stool examination and peripheral blood eosinophil count were normal in all patients. Strongyloidiasis was not suspected clinically in any patient and the diagnosis was achieved on endoscopic biopsy. Three of the patients with disseminated disease developed fatal Gram-negative systemic infection. This study highlights the importance of considering strongyloidiasis in all patients on immunosuppressive drug therapy who present with gastrointestinal symptoms so that the patient can be appropriately investigated and promptly treated. In endemic regions, patients with systemic Gram-negative bacterial infections without an obvious cause should be tested for strongyloidiasis.
TL;DR: The effectiveness of first-line regimens for stage 2 human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense infection in nine Médecins Sans Frontières HAT treatment programmes in Angola, Republic of Congo, Sudan and Uganda is described.
Abstract: This paper describes the effectiveness of first-line regimens for stage 2 human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense infection in nine Medecins Sans Frontieres HAT treatment programmes in Angola, Republic of Congo, Sudan and Uganda. Regimens included eflornithine and standard- and short-course melarsoprol. Outcomes for 10461 naive stage 2 patients fitting a standardised case definition and allocated to one of the above regimens were analysed by intention-to-treat analysis. Effectiveness was quantified by the case fatality rate (CFR) during treatment, the proportion probably and definitely cured and the Kaplan-Meier probability of relapse-free survival at 12 months and 24 months post admission. The CFR was similar for the standard- and short-course melarsoprol regimens (4.9% and 4.2%, respectively). The CFR for eflornithine was 1.2%. Kaplan-Meier survival probabilities varied from 71.4-91.8% at 1 year and 56.5-87.9% at 2 years for standard-course melarsoprol, to 73.0-91.1% at 1 year for short-course melarsoprol, and 79.9-97.4% at 1 year and 68.6-93.7% at 2 years for eflornithine. With the exception of one programme, survival at 12 months was >90% for eflornithine, whilst for melarsoprol it was <90% except in two sites. Eflornithine is recommended where feasible, especially in areas with low melarsoprol effectiveness.
TL;DR: What is known and what new evidence is needed to maximise the utility of rapid diagnostic tests for malaria in Africa are reviewed.
Abstract: After many years of development, rapid diagnostic tests (RDTs) for malaria are now being rolled out in many African countries to support the introduction of artemisinin-based combination therapies (ACT). RDTs create new opportunities both for improved care and as research tools, but it is important that the research agenda continues to address the many challenges, both operational and technical, that still need to be met. Here we review what is known and what new evidence is needed to maximise the utility of RDTs in Africa.
TL;DR: The findings highlight the magnitude of local necrosis, respiratory paralysis and antivenom failure in Spectacled cobra bite in Sri Lanka and require verification with robust laboratory tests.
Abstract: Summary In Sri Lanka, the Spectacled cobra ( Naja naja ) inflicts fatal bites. This hospital-based prospective study describes 25 cases of proven cobra bites, including 10 (40%) males and 15 (60%) females with a median age of 36 years (range 13–70 years). In 22 cases (88%) bites occurred in the daytime and in 13 cases (52%) they occurred at the victim's home compound. The site of the bite was the upper limb in 10 cases (40%), and 12 patients (48%) had applied a tourniquet. There were 5 dry bites (20%), 20 local reactions (80%), 9 cases of neurotoxicity (36%) and 3 cases of coagulopathy (12%). Eight patients (32%) had severe local necrosis—five underwent desloughing and skin grafting and two (including one of the above) had fasciotomy and compartmental decompression of the upper limb. Two patients died (case fatality rate 8%; 95% CI 0.98–26.03) due to rapidly spreading necrosis of the upper limb. Four patients (16%; 95% CI 4.53–36.08) developed respiratory paralysis; their median time from bite to assisted ventilation was 2 h (range 2–5 h) and the median duration of ventilation was 24 h (range 18–24 h). Envenomed patients received Indian polyvalent antivenom. The findings highlight the magnitude of local necrosis, respiratory paralysis and antivenom failure in Spectacled cobra bite in Sri Lanka. Coagulopathy requires verification with robust laboratory tests.
TL;DR: A cleaner, rodent-controlled environment may prevent exposure to scrub typhus and personal protection measures and better hygiene could further reduce individual risk.
Abstract: Summary To identify risk factors for scrub typhus in Darjeeling, India, we compared 62 scrub typhus cases (acute fever with eschar and specific IgM) with 62 neighbourhood controls. Cases were more likely to live close to bushes [matched odds ratio (MOR) 10; 95% CI 2.3–63] and wood piles (MOR 3.5; 95% CI 1.5–9.5), to work on farms (MOR 10; 95% CI 2.7–63), to observe rodents at home (MOR 3.6; 95% CI 1.4–11) and at work (MOR 9; 95% CI 2.4–57), and to rear domestic animals (MOR 2.4; 95% CI 1.1–5.7). Cases were less likely to wash after work (MOR 0.4; 95% CI 0.1–0.9) and change clothes to sleep (MOR 0.2; 95% CI 0.1–0.5). A cleaner, rodent-controlled environment may prevent exposure to scrub typhus. Personal protection measures and better hygiene could further reduce individual risk.
TL;DR: Data confirm the perception that women have a greater burden of trichiasis, and this burden persists across all populations studied, if the aim of eliminating blindness from trachoma is to be achieved.
Abstract: Summary It is widely accepted that women carry an increased burden of trachomatous trichiasis compared with men, but there is no systematic review of the available prevalence surveys in the peer-reviewed literature. A literature search was conducted to identify population-based trachoma prevalence surveys utilising the WHO simplified grading system that included data for trichiasis. Of 53 identified studies, 24 studies from 12 different countries met the inclusion criteria. Prevalence data were pooled in a meta-analysis to estimate an overall odds ratio (OR). The overall odds of trichiasis in women compared with men was 1.82 (95% CI 1.61—2.07). Individual survey ORs ranged from 0.83 (95% CI 0.40—1.73) in Myanmar to 3.82 (95% CI 2.36—6.19) in Ethiopia. There were statistically significant differences in odds of trichiasis by gender in 17 of 24 studies, all of which showed increased odds of trichiasis in women compared with men. These data confirm the perception that women have a greater burden of trichiasis, and this burden persists across all populations studied. Women must be specifically and deliberately targeted for trichiasis surgery if the aim of eliminating blindness from trachoma is to be achieved. © 2009 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.
TL;DR: Experiences gained thus far with the FLOTAC technique for diagnosing common soil-transmitted helminth infections are summarized and a single FLotAC has higher sensitivity than multiple Kato-Katz thick smears in detecting low-intensity infections.
Abstract: There is a tendency to neglect diagnostic issues in the era of 'preventive chemotherapy' in human helminthiases. However, accurate diagnosis cannot be overemphasized for adequate patient management and monitoring of community-based control programmes. Implicit is a diagnostic dilemma: the more effective interventions are in reducing helminth egg excretion, the less sensitive direct parasitological tests become. Here, experiences gained thus far with the FLOTAC technique for diagnosing common soil-transmitted helminth infections are summarized. A single FLOTAC has higher sensitivity than multiple Kato-Katz thick smears in detecting low-intensity infections. Further validation of the FLOTAC technique in different epidemiological settings is warranted, including diagnosis of intestinal schistosomiasis and food-borne trematodiases.
TL;DR: There are still specific needs for antigen detection in onchocerciasis, whilst standardisation of a panel of tools for LF will allow the definition of endpoint parameters so that countries can decide when mass drug administration (MDA) can be stopped and have a sensitive post-MDA surveillance system.
Abstract: Gold standard diagnosis using blood films or skin snips has dimished relevance as mass drug distribution programmes for control of filaria infections expand The view of 'diagnosis' and its relevance at the individual level has changed, as it has been recognised that the spectrum of programmatic processes (mapping, mass drug interventions, monitoring and evaluation, and surveillance) require different approaches as different questions are asked at each stage The feasibility and relevance of skin biopsy or blood film examination is challenged when mass drug distribution seeks to treat all eligibles in communities The need to expand programmes rapidly by identifying the highest risk communities has seen the development of rapid assessment methods, such as rapid epidemiological mapping of onchocerciasis (REMO) and rapid epidemiological assessment (REA) for onchocerciasis, immunochromatographic test (ICT)-based mapping for lymphatic filariasis (LF), and Rapid Assessment Procedure for Loiasis (RAPLOA) for Loa, to reduce the risk of serious adverse events and to guide projects in high-risk communities As programmes reduce the prevalence through mass drug distribution, more sensitive techniques are required to define endpoints, for LF in particular where the programmatic goal is elimination; for onchocerciasis, sensitive surveillance tools are required particularly in those areas where such risks of recrudescence are high Whilst much progress has been made in the development and deployment of rapid methods, there are still specific needs for antigen detection in onchocerciasis, whilst standardisation of a panel of tools for LF will allow the definition of endpoint parameters so that countries can decide when mass drug administration (MDA) can be stopped and have a sensitive post-MDA surveillance system
TL;DR: Although Zahedan is an area with poor hygiene located in a tropical area near the border of Pakistan and Afghanistan, the prevalence of E. histolytica and E. dispar here compared with other parasites and infectious diseases is unexpectedly low.
Abstract: We investigated the prevalence of intestinal protozoan parasites in patients with gastrointestinal complaints in medical centers in Zahedan, Iran. A total of 1562 stool samples was examined from July 2004 to January 2006 using microscopy (direct smear, formalin-ether concentration), xenic culture and PCR techniques. Four hundred and twenty-seven (27.3%) of the patients were infected with one or more intestinal parasites. Giardia lamblia (10.1%), Entamoeba coli (10%), E. hartmanni (1.7%), Blastocystis hominis (2.2%), Chilomastix mesnili (1.7%), Trichomonas hominis (0.7%), E. histolytica/E. dispar (0.51%) and Iodamoeba butschlii (0.45%) were the most prevalent protozoa detected with microscopy. Of the eight microscopy-positive E. histolytica/E. dispar samples, six were identified as E. dispar by PCR/gel electrophoresis, whereas E. histolytica was not detected at all. Although Zahedan is an area with poor hygiene located in a tropical area near the border of Pakistan and Afghanistan, the prevalence of E. histolytica and E. dispar here compared with other parasites and infectious diseases is unexpectedly low.