Abstract The control of human onchocerciasis (river blindness) is one of the most successful global partnerships ever supported by the World Bank. Mectizan mass treatments have greatly contributed to this success and have shaped the strategies of the programmes in which the World Bank has been involved — the Onchocerciasis Control Programme (OCP), which covered onchocerciasis control in West Africa until 2002, and the African Programme for Onchocerciasis Control (APOC), which is currently working in 30 countries, to protect millions of people from onchocerciasis. Through the strategy of community-directed treatment with ivermectin (CDTI), onchocerciasis control in Africa was transformed from a technologically-driven and vertical health initiative to a community-directed process of treatment and empowerment. Together, CDTI and the donation of Mectizan also reduced costs, producing one of the most effective and affordable disease-control schemes ever seen, and the CDTI strategy is now being applied to other disease-control initiatives. The onchocerciasis programmes have also been exemplary in shaping partnerships with communities, countries, the World Health Organization, governments, non-governmental development organizations, and the private sector. The Bank's involvement in onchocerciasis control has helped mobilize funds, giving confidence to other donors. More than U. S.$800 million was raised for both the OCP and APOC (excluding the initial costs of Mectizan). With these funds and the commitment of the partners involved, high coverages have been achieved in the Mectizan distributions. The Bank is confident that, during the years to come, the partners will continue their success, and that the APOC will achieve its goals by the target date for its closure, in 2015.
Abstract The control of human onchocerciasis (river blindness) is one of the most successful global partnerships ever supported by the World Bank. Mectizan mass treatments have greatly contributed to this success and have shaped the strategies of the programmes in which the World Bank has been involved — the Onchocerciasis Control Programme (OCP), which covered onchocerciasis control in West Africa until 2002, and the African Programme for Onchocerciasis Control (APOC), which is currently working in 30 countries, to protect millions of people from onchocerciasis. Through the strategy of community-directed treatment with ivermectin (CDTI), onchocerciasis control in Africa was transformed from a technologically-driven and vertical health initiative to a community-directed process of treatment and empowerment. Together, CDTI and the donation of Mectizan also reduced costs, producing one of the most effective and affordable disease-control schemes ever seen, and the CDTI strategy is now being applied to other disease-control initiatives. The onchocerciasis programmes have also been exemplary in shaping partnerships with communities, countries, the World Health Organization, governments, non-governmental development organizations, and the private sector. The Bank's involvement in onchocerciasis control has helped mobilize funds, giving confidence to other donors. More than U. S.$800 million was raised for both the OCP and APOC (excluding the initial costs of Mectizan). With these funds and the commitment of the partners involved, high coverages have been achieved in the Mectizan distributions. The Bank is confident that, during the years to come, the partners will continue their success, and that the APOC will achieve its goals by the target date for its closure, in 2015.
In order to obtain more information about the population structure of Chilean Trypanosoma cruzi, and their genetic relationship with other Latino American counterparts, we performed the study of T. cruzi samples detected in the midgut content of Triatoma infestans insects from three endemic regions of Chile. The genetic characteristics of these samples were analysed using microsatellite markers and PCR conditions that allow the detection of predominant T. cruzi clones directly in triatomine midgut content. Population genetic analyses using the Fisher’s exact method, analysis of molecular variance (AMOVA) and the determination of FST showed that the northern T. cruzi population sample was genetically differentiated from the two southern population counterparts. Further analysis showed that the cause of this genetic differentiation was the asymmetrical distribution of TcIII T. cruzi predominant clones. Considering all triatomines from the three regions, the most frequent predominant lineages were TcIII (38%), followed by TcI (34%) and hybrid (8%). No TcII lineage was observed along the predominant T. cruzi clones. The best phylogenetic reconstruction using the shared allelic genetic distance was concordant with the population genetic analysis and tree topology previously described studying foreign samples. The correlation studies showed that the lineage TcIII from the III region was genetically differentiated from the other two, and this differentiation was correlated with geographical distance including Chilean and mainly Brazilian samples. It will be interesting to investigate whether this geographical structure may be related with different clinical manifestation of Chagas disease.
Ticks are obligate haematophagous ectoparasites of various animals, including humans, and are abundant in temperate and tropical zones around the world. They are the most important vectors for the pathogens causing disease in livestock and second only to mosquitoes as vectors of pathogens causing human disease. Ticks are formidable arachnids, capable of not only transmitting the pathogens involved in some infectious diseases but also of inducing allergies and causing toxicoses and paralysis, with possible fatal outcomes for the host. This review focuses on tick paralysis, the role of the Australian paralysis tick Ixodes holocyclus, and the role of toxin molecules from this species in causing paralysis in the host.
As the information available on the treatment of angiostrongyliasis with a combination of albendazole and dexamethasone is limited, the efficacy of such therapy was assessed using data collected during the 2006 outbreak of angiostrongyliasis in Beijing. In a retrospective and controlled study, 35 patients treated with albendazole-dexamethasone (given 20 mg albendazole/kg and 3 mg dexamethasone daily for 7 days) were compared with 34 controls who were treated only symptomatically (with acetaminophen or other drugs). Compared with the controls, the patients given the combination were less likely to have headaches after 7 days (P = 0·038), tended to have headaches that cleared quicker (P = 0·010), and received fewer doses of acetaminophen (P = 0·036). Since no serious adverse effects were observed, a 1-week treatment with a combination of albendazole and dexamethasone appears both safe and beneficial in the treatment of angiostrongyliasis.
The most recent, large-scale survey on human urinary schistosomiasis (caused by Schistosoma haematobium) and human intestinal schistosomiasis (caused by S. mansoni) in Cameroon, which was carried out in 1986, revealed that both diseases were endemic throughout Far North province (Ratard et al., 1990). In a survey in 2008–2009, Massenet et al. (2009) found that the prevalences of these diseases in the neighbouring North province were markedly lower than those recorded by Ratard et al. (1990), in the same area, about two decades earlier. Since antischistosomal treatment has never been delivered at community level in North province, the reasons behind this favourable trend were (and remain) unclear. The aim of the present, cross-sectional survey, conducted in 25 primary schools in 2009, was to see if urinary schistosomiasis and intestinal schistosomiasis had shown a similar decline in Far North province, from the prevalences of 35% and 9%, respectively, recorded among schoolchildren in 1986 (Ratard et al., 1990). Lot quality assurance sampling (LQAS) was used, previous studies having shown this to be a cost-effective method of identifying communities that qualify for treatment (Rabarijaona et al., 2003; Brooker et al., 2005). The 25 surveyed schools (see Figure) were those previously investigated, in 1986, by Ratard et al., (1990). In each school, eight boys and seven girls were randomly selected from an exhaustive list of the children aged 9–11 years who were present on the day of the survey. Human infection with S. mansoni or S. haematobium is considered hyper-endemic in a community when eggs are observed in at least 50% of stool or urine samples, respectively. In each study school, for each of these schistosome species, the null hypothesis (H0) that the prevalence of infection was ⩾50% among all the schoolchildren was therefore explored. Using the LQAS method, the null hypothesis was accepted if at least four of the 15 children investigated were observed to be excreting the eggs of the schistosome of interest (this sampling plan gives a 95% probability of the null hypothesis being accepted when the prevalence is ⩾50%, as well as an 80% probability of schistosomiasis being categorized as not hyper-endemic in a school where the prevalence of infection is <20%). The locations of the schools surveyed in the Logone et Chari (1), Mayo Danay (2), Kaele (3), Diamare (4), Mayo Sawa (5) and Mayo Tsanaga (6) departments of Far North province in 2009, showing the schools where Schistosoma haematobium was ... Each subject was given a stool container (including a specimen-collection spoon) and a urine container and asked to collect fresh stool and urine specimens between 10·00 and 15·00 hours. On the day of their collection, the stool specimens were checked for S. mansoni eggs as Kato–Katz smears (Katz et al., 1972) while 10 ml of each urine sample were checked for S. haematobium eggs, by membrane filtration (WHO, 1985). The locations of the 11 schools where S. haematobium infection was considered hyper-endemic are shown in the Figure. None of the surveyed schools was found hyper-endemic for S. mansoni. After aggregation of the collected data, by department (see Table), the recorded prevalences of S. haematobium infection were found to be significantly higher in the Mayo Danay department than in any other department in Far North province (P<0·0001). In 1979, a dam was built in Mayo Danay, to support the large-scale cultivation of irrigated rice, and it may be the resultant lake (Lake Maga), wetlands and irrigation canals that support relatively high levels of S. haematobium transmission in the department. Six of the 11 schools found hyper-endemic for S. haematobium lie within Mayo Danay. The other five such schools are scattered throughout the other departments of Far North province (with low prevalences of S. haematobium infection recorded in neighbouring schools; see Figure). Such heterogeneity in the distribution of schistosomiasis in the province is similar to that observed in North province, in 2008–2009, by Massenet et al. (2009). Comparative results of the 1986 and 2009 examinations of urine samples (from schoolchildren in six departments of Far North province) for the eggs of Schistosoma haematobium Schistosoma mansoni now appears to be relatively rare in Far North province, with no schools considered hyper-endemic for this parasite and only five (1·3%) of the 375 tested children found to be co-infected with S. mansoni and S. haematobium. Although the results of such comparison must be interpreted with care, because the two surveys used different sampling methods, the Table allows the results of the survey in Far North province in 1986 study (Ratard et al., 1990) to be compared with those recorded in 2009 (present study). The mean prevalence of S. haematobium infection detected in the schoolchildren of Far North province in 2009 (33%) was very similar to that recorded in 1986 (35%) but the geographical distribution of such infection appears to have changed markedly between the two surveys. For example, the prevalence of such infection in Mayo Danay department (which, in 1986, was close to the median value for all the other departments of the province) appears to have markedly increased. The mean prevalence of S. mansoni infection among the schoolchildren of Far North province seems to have decreased between the surveys, from 9% in 1986 to 4% in 2009 (P = 0·001), without any delivery of antischistosomal treatment at community level. A similar decrease in the prevalence of schistosomal infection, in the absence of any systematic praziquantel treatment, was found to have occurred in neighbouring North province in 2008–2009 (Massenet et al., 2009). The reason behind the temporal and geographical changes seen in the prevalence of schistosomal infection in northern Cameroon, in the absence of community-level treatment, merit further research.
Ticks are obligate haematophagous ectoparasites of various animals, including humans, and are abundant in temperate and tropical zones around the world. They are the most important vectors for the pathogens causing disease in livestock and second only to mosquitoes as vectors of pathogens causing human disease. Ticks are formidable arachnids, capable of not only transmitting the pathogens involved in some infectious diseases but also of inducing allergies and causing toxicoses and paralysis, with possible fatal outcomes for the host. This review focuses on tick paralysis, the role of the Australian paralysis tick Ixodes holocyclus, and the role of toxin molecules from this species in causing paralysis in the host.
Nine cases of cryptosporidiosis co-infections in AIDS patients were clinically categorised into severe (patients 1, 3, 8 and 9), moderate (patients 4 and 5) and mild (patients 2, 6 and 7). Formalin-fixed faecal specimens from these patients were treated to obtain high quality DNA competent for amplification and sequencing of the 60-kDa glycoprotein (GP60) gene. Sequence analysis revealed that one patient was infected with Cryptosporidium hominis whereas the remaining eight patients were infected with C. parvum. Interestingly, the patients showing severe cryptosporidiosis harboured two subtypes within the C. parvum allelic family IIc (IIcA5G3 and IIcA5G3R2), whereas patients with moderate or mild infections showed various subtypes of the C. parvum allelic family IIa (IIaA14G2R1, IIaA15G2R1, IIaA17G3R1 and IIaA18G3R1).DNA extraction and genotyping of Cryptosporidium spp. is a challenging task on formalin-fixed stool samples, whose diagnostic outcome is age-dependent. The method herein reported represents a step forward routine diagnosis and improves epidemiology of HIV-related clinical cases. Due to the need to elucidate genetic richness of Cryptosporidium human isolates, this approach represents a useful tool to correlate individual differences in symptoms to subgenotyping lineages.
Hepatic capillariasis is a serious parasitic zoonosis caused by the tissue-dwelling nematode Calodium hepaticum (Bancroft, 1893) — commonly known as Capillaria hepatica. It is a parasite found in t...
Compared with the corresponding values for the untreated (control) mice.{ Significant reduction compared with control (P,0.05).{ Very significant reduction compared with control (P,0.01). *Compared with the corresponding values for the untreated (control) mice.
Listeria monocytogenes is a foodborne pathogen associated with severe diseases in humans and animals. The genotypic analysis of 17 L. monocytogenes isolates recovered from humans in India during 2006-2009 using multiplex serotyping PCR allowing serovar predictions, conventional serology and by pulsed field gel electrophoresis (PFGE) is presented. The isolates were recovered from patients exhibiting various clinical conditions. A multiplex-PCR based serotyping assay revealed 88·24% (15/17) of the strains belonging to the serovar group 4b, 4d, 4e and 11·76% (2/17) to the serovar group 1/2b, 3b. Conventional serology indicated that 13 (76·47%) L. monocytogenes isolates to be of serotype 4b, 2 (11·76%) serotype 4d, and 2 (11·76%) serotype 1/2b. Ten ApaI and nine AscI pulsotypes were recognized among the 17 human isolates. PFGE analysis allowed discrimination among isolates of the same serotype and among isolates from the same sampling areas or those isolated from different areas. Thus, PFGE together with multiplex-PCR serotyping allows rapid discrimination of L. monocytogenes strains. In addition, the predominance of L. monocytogenes serotype 4b is of concern, as this serotype has been most frequently associated with human listeriosis outbreaks.
Between June 2008 and March 2009, a cross-sectional study of human malaria was carried out in four governorates of Yemen, two (Taiz and Hodiedah) representing the country's highlands and the others (Dhamar and Raymah) the country's coastal plains/foothills. The main aims were to determine the prevalences of Plasmodium infection among 455 febrile patients presenting for care at participating health facilities and to investigate the potential risk factors for such infection. Malarial infection was detected in 78 (17·1%) of the investigated patients and was more likely to be detected among the febrile patients from the highlands than among those presenting in the coastal plains/foothills (22·6% v.13·9%; χ(2)=10·102; P=0·018). Binary logistic-regression models identified low household income [odds ratio (OR)=13·52; 95% confidence interval (CI)=2·62-69·67; P=0·002], living in a household with access to a water pump (OR=4·18; CI=1·60-10·96; P=0·004) and living in a household near a stream (OR=4·43; CI=1·35-14·56; P=0·014) as significant risk factors for malarial infection in the highlands. Low household income was the only significant risk factor identified for such infection in the coastal plains and foothills (OR = 8·20; CI=1·80-37·45; P=0·007). It is unclear why febrile patients in the highlands of Yemen are much more likely to be found to have malarial infection than their counterparts from the coastal plains and foothills. Although it is possible that malarial transmission is relatively intense in the highlands, it seems more likely that, compared with those who live at lower altitudes, those who live in the highlands are less immune to malaria, and therefore more likely to develop febrile illness following malarial infection. Whatever the cause of the symptomatic malarial infection commonly found in the highlands of Yemen, it is a matter of serious concern that should be addressed in the national strategy to control malaria.
Background: Thrombocytopenia has been reported in the majority of malaria studies. Some but not all studies suggest the possible role of platelets in the pathology of severe malaria. We assess the association of admission platelet count with malaria complications and mortality in vivax and falciparum malaria.Methods: This is a prospective, observational study of patients aged 18 years and above admitted in a tertiary care teaching hospital from August 2004 to July 2006 in Manipal, India. Malaria was diagnosed based on clinical features along with positive Quantitative Buffy Coat method (QBC MP) or thin blood smear examination (Giemsa stain). Platelet counts were measured using Coulter LH 756 Analyser. Thrombocytopenia was defined as a platelet count <150 x 10(9)/l.Results: A total of 131 consecutive patients were included. Sixty patients (46%) were infected with Plasmodium vivax and the rest with Plasmodium falciparum. Forty-six (35%) patients had non-severe and 24 (18%) had severe falciparum infection. The prevalence of thrombocytopenia was similar in vivax and falciparum malaria. Patients with severe falciparum malaria had a statistically significant lower platelet count (P=0.01) compared to non-severe falciparum malaria. Severe malaria patients with renal failure (P=0.02) or hyperparasitaemia (P=0.03) had a statistically significant lower mean platelet count compared to non-severe falciparum malaria. Patients with involvement of more than one organ system had a lower mean platelet count compared to those with single organ involvement.Conclusions: The incidence of thrombocytopenia was similar in vivax and falciparum malaria. The admission platelet count is significantly lower in patients who have hyperparasitaemia and acute renal failure compared to patients without complications.
In patients with Strongyloides stercoralis infection, a dysregulation of host immunity can lead to hyperinfection syndrome (HS) and disseminated strongyloidiasis (DS), characterized by high fatality rate. HS has been reported in HIV-positive patients following use of corticosteroids or during immune reconstitution inflammatory syndrome (IRIS). A retrospective study was conducted to estimate the prevalence of S. stercoralis infection among HIV-positive immigrants, attending two Italian hospitals. From January 2000 to August 2009, 138 HIV-positive immigrants were systematically screened for strongyloidiasis, as a part of their routine care, with an indirect immunofluorescent antibody test (IFAT) developed at the Centre for Tropical Diseases, Sacro Cuore Hospital of Negrar, Verona. The majority were also submitted to stool examination. Fifteen (11%) resulted infected by S. stercoralis, of whom four (27%) had a negative serology (diagnosis made with stool examination). A higher eosinophil count (0·94 versus 0·24×10(9)/l, P<0·01) and more frequent gastrointestinal and cutaneous symptoms (odds ratio: 4·8 and 5·8, respectively) were found in patients with strongyloidiasis compared with controls. The IFAT is more sensitive than direct parasitological methods. The proportion of false negative results was higher than expected based on the theoretical test sensitivity. Considering the high prevalence detected and the apparent, lower sensitivity of serology, we propose a systematic screening for Strongyloides infection, with both serology and stool culture, for all HIV-positive immigrants coming from endemic areas.
Dicrocoelium dendriticum, commonly known as the Lancet liver fluke, is endemic in the Old World since prehistoric times (Le Bailly and Bouchet, 2010). D. dendriticum is distributed worldwide. The adults of D. dendriticum are 5 to 15 mm in length and 1.5–2.5 mm in width. They live in the bile ducts of the definitive host (ruminants such as cow and sheep). The eggs excreted in faeces are mainly ingested by land snails of the Helicella, Theba and Zebrina genera. The definitive host gets infected by eating vegetation with ants mainly of the genus Formica infected with metacercariae. The young flukes move to the liver and start laying eggs after 10–12 weeks (Bartolome et al., 1987; Karadag et al., 2005). Human infection is very rare and occurs through accidental ingestion of infected ants by eating unwashed raw vegetables or drinking contaminated water (Acha and Szyfres, 2005). Although the subclinical form predominates (Saucas et al., 1989), it can produce chronic cholangitis and dilatation, swelling or adenomatous proliferation in the bile ducts. Spurious infection is more frequently observed after ingesting raw liver of infected animals with eggs or adult worms (Saucas et al., 1989; Diaz et al., 2007). The diagnosis of a true infection is carried out through close examination of faeces after a diet free from raw herbivore animal food (Wolfe, 2007). The lack of observation of eggs after a strict diet would indicate that it is a spurious infection. The standard treatment is with Praziquantel or Triclobendazol, but in case of spurious infection, treatment is not recommended, except the elimination of raw animal viscera from diet. In Spain there is a high prevalence of D. dendriticum in animals, increasing in mountainous areas or flat land with limestone (Otranto and Traversa, 2002; Duchacet and Lamka, 2003), with rates of 23 to 100% (Wolfe, 2007; Magi et al., 2009). Controlling this parasite in livestock is particularly difficult, due to the diversity of the definitive hosts that can be affected, the unspecificity of intermediate hosts and the complex biological life cycle (Otranto and Traversa, 2002). The province of Almeria (Southern Spain) has highly increased the number of foreigners over recent years, from 17.4% in 2008 to 20.8% in 2009 [data from the national Institute for Statistics (INE). They come mainly from countries with low income (Morocco, Romania, Latin America, Senegal, Russia and Mali). A monitoring study was carried out including all patients from our health area with presence of D. dendriticum eggs in faeces, from November 2005 (first case reported) to 31 December 2008 (Cabeza et al., 2007). The parasitological study of stools was carried out after the concentration of faeces (modified Ritchie method) (Ritchie, 1948) and subsequent visualization with an optical microscope. To determine whether it was a true or spurious infection, parasitological study was repeated after subjecting the patient to a meat and viscera-free diet during the 3 days prior to collecting the stool sample. The epidemiological study was carried out through an epidemiological survey of the patients at the Tropical Medicine Unit of our hospital or a revision of the Clinical history and subsequent storage in an encrypted database using SPSS 15 for statistical analysis. During the study, we analyzed 12 246 samples finding eggs of D. dendriticum in the stools of 75 foreign patients; mainly from Sub-Saharan Africa, a smaller proportion from Maghreb and just one patient, from Romania. The average age of the population was 29 years (range 9 to 55). The isolations in years were: 1 (1.3%) patient in 2005, 11 (14.7%) patients in 2006, 11 (14.7%) patients in 2007 and 52 (69.3%) patients in 2008, with the following confidence interval and prevalence values per year (Table 1). A total of 98.7% of the patients lived in Western Almeria, 89.3% (67 cases) of them belonged to the municipality of Roquetas (77 423 inhabitants in 2008-Data provided by the INE). Of these 75 cases, only 39 patients have been included in this study, 3 women and 36 men. The average age was 28.6 (9–47) years, with an average time of residence in Spain of 27 months (range 2 to 72). Table 1 Prevalence of D. dendriticum per years The epidemiological study of the studied population is reflected in Table 2. Table 2 Epidemiological study Due to the peculiarities of the life cycle of D. dendriticum, infection in humans is very rare, as it takes place through the ingestion of ants containing the metacercaria (infective form). In humans, it is common to find the parasite in the form of a ‘parasite in transit’, after eating raw or undercooked liver of herbivores containing adult specimens of this species (Bada, 1988; Saucas et al., 1989; Schweiger and Kuhn, 2008). Our study includes a large number of cases, all of them spurious infections as there were no visualizations of D. dendriticum eggs after following a diet free from animal meat or viscera during the 3 days prior to collecting the samples. Of all the cases studied, only two patients stated that they had eaten raw liver, the rest ate it cooked or did not eat it at all, therefore it seems that the infestation or false parasitation could be due to consumption of the viscera annexes of these animals. Although among the symptoms of a true parasitation are constipation, cholangitis, biliary obstruction, chronic diarrhoea, abdominal pain and hepatomegaly (Magi et al., 2009), only 60% of the patients presented abdominal pain at the time of the visit and 18% of the patients had sporadic cases of diarrhoea, probably due to other concomitant parasitations (Strongyloides stercoralis, Trichuris trichiura, etc.). In addition, the elimination from the diet of raw or poorly cooked liver of these animals and the subsequent parasitological study confirmed these results as no eggs of the parasite were observed after the diet (Zabala Martin–Gil et al., 2007), confirming that they were spurious infections. There are many studies carried out in Spain and in other countries (Diaz et al., 2007) showing that it is more frequent in areas with a higher altitude and lower temperatures where land molluscs predominate. These climate and orographic conditions are in Western Almeria (Duchacet and Lamka, 2003; Manga et al., 1995; Biggeri et al., 2007). The most favourable climate conditions for the infection of the definitive host is autumn as there are abundant pastures, humidity and a large amount of molluscs discharging cercariae (Manga et al., 1995; Manga–Gonzalez et al., 2001). Spring contamination depends on the survival through winter of the molluscs infected in autumn, being lower in cold winter years. In conclusion, the greatest risk of dicroceliosis in animals (lambs, calves, etc.) in dry and arid areas is in late winter–spring and autumn (Manga et al., 1995). The factor that has the most influence in the number of isolated cases of D. dendriticum, is the type of population attended at our hospital: foreign patients whose culture, eating habits and religious beliefs, influence the kind of food they consume, like eating lamb instead of pork which is forbidden by their religion or the belief that the consumption of viscera (liver) strengthens them. It is important to notice that this parasite has not been detected in any native patient. Another aspect worth noticing is the eating habits regarding meat among this population, as a high proportion (almost half of the respondents) sacrifice the animal at their own homes without any sort of veterinary control, or purchase meat in premises specialized in products of Maghrebian origin. All patients were advised to buy meat and its derivatives at authorized premises. It would be interesting to know the prevalence rates of parasitation of this trematode in herbivore animals in our region as the studies carried out in Spain were from the northern region (Diaz et al., 2007; Perez et al., 2008; Manga–Gonzalez and Gonzalez–Lanza, 2005). Due to the high number of spurious infections detected, the hygienic-sanitary measures should be reinforced offering appropriate information by social mediators or trained medical staff, as long as the veterinary controls, because the conditions are appropriate for a true infection to take place. We must also pay attention to the clinical development of all cases.
The involvement of members of the Anopheles gambiae complex Giles and An. funestus Giles and An. nili Theobald groups in the transmission of Plasmodium falciparum was recently investigated in the villages of Gbatta and Kpehiri, which lie, respectively, in forest areas in the west and south of Cote d'Ivoire.Adult female mosquitoes were collected, using human landing catches, inside and outside dwellings. After identification and dissection, the heads and thoraces of all the anopheline mosquitoes were tested, in an ELISA, for circumsporozoite protein (CSP). All the female anopheline mosquitoes collected and identified to species using PCR were found to be An. gambiae s.s., An. nili s.s. or An. funestus s.s., with An. gambiae s.s. and An. funestus s.s. predominant in Gbatta but An. nili s.s. the most common species in Kpehiri. In Gbatta, 3.1% of the female An. gambiae collected, 5.0% of the female An. funestus and 1.8% of the female An. nili were found CSP-positive. The corresponding values in Kpehiri were even higher, at 5.9%, 6.2% and 2.4%, respectively. The estimated entomological inoculation rates (EIR) were very high: 302 infected bites (139 from An. gambiae, 146 from An. funestus and 17 from An. nili)/person-year in Gbatta and 484 infected bites (204 from An. gambiae, 70 from An. funestus and 210 from An. nili)/person-year in Kpehiri.In Gbatta, An. gambiae s.s. was responsible for most of the rainy-season transmission while An. funestus became the main malaria vector in the dry seasons. In Kpehiri, however, An. nili appeared to be the main vector throughout the year, with An. gambiae of secondary importance and An. funestus only becoming a significant vector during the rainy season. Although, in both study sites, intense transmission was therefore occurring and the same three species of anopheline mosquito were present, the relative importance of each mosquito species in the epidemiology of the human malaria at each site differed markedly.
Although, when applied under controlled conditions in India and Nepal, indoor residual spraying (IRS) has been found to reduce sandfly densities significantly, it is not known if IRS will be as effective when applied generally in these countries, via the national programmes for the elimination of visceral leishmaniasis. The potential benefits and limitations of national IRS programmes for the control of sandflies were therefore evaluated in the districts of Vaishali (in the Indian state of Bihar), Sarlahi (in Nepal) and Sunsari (also in Nepal). The use of technical guidelines, levels of knowledge and skills related to spraying operations, insecticide bio-availability on the sprayed surfaces, concentrations of the insecticide on the walls of sprayed houses, insecticide resistance, and the effectiveness of spraying, in terms of reducing sandfly densities within sprayed houses (compared with those found in unsprayed sentinel houses or control villages) were all explored. It was observed that IRS programme managers, at district and subdistrict levels in India and Nepal, used the relevant technical guidelines and were familiar with the procedures for IRS operation. The performance of the spraying activities, however, showed important deficiencies. The results of bio-assays and the chemical analysis of samples from sprayed walls indicated substandard spraying and suboptimal concentrations of insecticide on sprayed surfaces. This was particularly obvious at one of the Nepali study sites (Sunsari district), where no significant vector reduction was achieved. Sandfly resistance to the insecticide used in India (DDT) was widespread but the potential vectors in Nepal remained very susceptible towards a pyrethroid similar to the one used there. The overall short-term effectiveness of IRS was found to be satisfactory in two of the three study sites (in terms of reduction in the densities of the sandfly vectors). Unfortunately, the medium-term evaluation, conducted 5 months after spraying, was probably made invalid by flooding or lime plastering in the study areas. Preparation for, and the monitoring of, the IRS operations against sandfly populations in India and Nepal need to be improved.
Ongoing transmission of lymphatic filariasis (LF) was assessed in five Samoan villages by measuring microfilaraemia (Mf), circulating filarial antigen (CFA) and antibody prevalence. Compared to the other villages, Fasitoo-Tai had a significantly higher Mf prevalence (3·2%), CFA prevalence (14·6%) and antibody prevalence in children (62·0%) (P<0·05). Puapua had a significantly lower CFA prevalence (2·5%), no detectable Mf-positive individuals and significantly low antibody prevalence in children (7·9%) (P<0·05). Siufaga, previously believed to be LF-free, recorded >1% CFA prevalence and a high antibody prevalence in children (46·6%). Overall, antibody prevalence in children appeared to reflect the transmission dynamics in the villages and, in Siufaga, identified an area of ongoing transmission. The Filariasis Cellabs Enzyme-Linked Immunosorbent Assay (CELISA), based on recombinant antigen Bm14, to detect antibodies, could potentially be a promising diagnostic tool for inclusion in future surveillance in the South Pacific.
