Control of malaria outbreak due to Plasmodium vivax in Aswan Governorate, Egypt.

In 2014, after several years of maintaining zero malaria indigenous cases, Egypt had an outbreak of Plasmodium vivax: 21 confirmed cases during May-June 2014. In response to the outbreak, the Ministry of Health and Population (MoHP) launched an emergency response through early detection and prompt treatment of cases, vector control, public education and intersectoral collaboration. Twenty cases (95.2%) were residents of El-Sheikh Mostafa village, Edfu district, Aswan governorate, southern Egypt. All cases, consequent to the index case were identified through house-to-house surveillance visits. One P. falciparum-infected case was also identified in the same village. Treatment of all infected cases was initiated following laboratory confirmation. The MoHP's rapid response to and containment of the outbreak demonstrates the institutional capacity for detection and control of outbreaks which can occur after elimination.

Control of malaria outbreak due to Plasmodium vivax in Aswan governorate, Egypt

In 2014, after several years of maintaining zero malaria indigenous cases, Egypt had an outbreak of Plasmodium vivax: 21 confirmed cases during May-June 2014. In response to the outbreak, the Ministry of Health and Population [MoHP] launched an emergency response through early detection and prompt treatment of cases, vector control, public education and intersectoral collaboration. Twenty cases [95.2%] were residents of El-Sheikh Mostafa village, Edfu district, Aswan governorate, southern Egypt. All cases, consequent to the index case were identified through house-to-house surveillance visits. One P. falciparum-infected case was also identified in the same village. Treatment of all infected cases was initiated following laboratory confirmation. The MoHP's rapid response to and containment of the outbreak demonstrates the institutional capacity for detection and control of outbreaks which can occur after elimination

En 2014, après s'être maintenue plusieurs années sans aucun cas autochtone de paludisme, legypte a connu une flambée de Plasmodium vivax : 21 cas confirmés entre mai et juin 2014. En réponse à la flambée, le ministère égyptien de la Santé publique et de la Population a mis en place un plan d'urgence comprenant le dépistage précoce et le traitement rapide des cas, la lutte antivectorielle, la sensibilisation du public et la collaboration intersectorielle. Vingt de ces cas [95,2 %] se sont déclarés chez des résidents du village d'El-Sheikh Mostafa, dans la circonscription d'Edfou [Gouvernorat d'Assouan, au sud de legypte]. Suite au cas indicateur, la totalité des cas a été identifiée grâce aux visites de surveillance effectuées au porte-à-porte. Un cas d'infection à P. falciparum a également été identifié dans le même village. Après confirmation en laboratoire, le traitement de l'ensemble des cas infectés a été entrepris. La réponse rapide du ministère de la Santé publique et de la Population et l'endiguement de la flambée attestent de ses moyens institutionnels pour la détection, la confirmation et le traitement du paludisme, ainsi que la maîtrise des flambées susceptibles de survenir après l'élimination de la maladie

Impact of polystyrene beads as a mosquito control measure to supplement lymphatic filariasis elimination activities in Socotra Island, Yemen.

Lymphatic filariasis (LF) is targeted for worldwide elimination. In Yemen, all mainland implementation units met the WHO criteria for stopping mass drug administration (MDA) after 5 rounds. However, in Socotra Island these criteria were not met. Our study evaluated the efficacy of applying expanded polystyrene beads (EPBs) on the Culex population and the effect on LF transmission. Human and mosquito surveys were conducted in 40 randomly selected households in Hadibo (capital of Socotra) before and after application of EPBs. The EPBs intervention resulted in a reduction in mosquito density of 80% and a 64.3% reduction in microfilaria prevalence. The majority of interviewed households (98%) thought EPBs considerably reduced the mosquito population. After the intervention all collected pools tested negative. Application of EPBs is an effective supplement to MDA for achieving the goal of LF elimination.

Cross-reaction of antigen preparations from adult and larval stages of the parasite Setaria equina with sera from infected humans with Wuchereria bancrofti.

Crude antigenic preparations from Setaria equina were used in ELISA and Western blotting to examine cross-reaction with human sera from areas endemic for bancroftian filariasis. Sera from normal subjects from non-endemic areas were included as negative controls. Cross-reaction was found between S. equina antigens and antibodies in the sera of Wuchereria bancrofti-infected patients, with the highest levels observed between sera of chronic infected patients and Setaria spp. crude female worm surface antigen (CFSWA). In the absence of active transmission of Setaria spp. infection, CFWSA is useful to detect chronic W. bancrofti infection before patients become symptomatic, particularly when chronic patients are known to be amicrofilaraemic. In the presence of active S. equina infection, antigens from the adult and microfilaraemic stages showed the highest degree of cross-reaction with human sera.

Impact of polystyrene beads as a mosquito control measure to supplement lymphatic filariasis elimination activities in Socotra Island, Yemen

Lymphatic filariasis [LF] is targeted for worldwide elimination. In Yemen, all mainland implementation units met the WHO criteria for stopping mass drug administration [MDA] after 5 rounds. However, in Socotra Island these criteria were not met. Our study evaluated the efficacy of applying expanded polystyrene beads [EPBs] on the Culex population and the effect on LF transmission. Human and mosquito surveys were conducted in 40 randomly selected households in Hadibo [capital of Socotra] before and after application of EPBs. The EPBs intervention resulted in a reduction in mosquito density of 80% and a 64.3% reduction in microfilaria prevalence. The majority of interviewed households [98%] thought EPBs considerably reduced the mosquito population. After the intervention all collected pools tested negative. Application of EPBs is an effective supplement to MDA for achieving the goal of LF elimination

A retrospective hospital study of human cystic echinococcosis in Egypt.

We performed a retrospective study to determine annual clinical incidence of human cystic echinococcosis (CE) in 14 Egyptian hospitals between January 1997 and December 1999. From 492 353 records examined, 133 (0.027%) new human CE cases were recorded. Of these, 50 (37.6%) were from Alexandria and Matrouh hospitals, 33 (24.8%) from Giza Chest Hospital and 50 from other regions. Matrouh governorate had the highest annual clinical incidence (1.34-2.60 per 100 000) followed by Giza governorate (0.80-1.16 per 100 000). About a third of those affected were aged < or = 20 years. Liver and lungs were the organs most affected. Although human CE is of low endemicity in Egypt, it may-represent a public health concern in Matrouh and Giza governorates.

A retrospective hospital study of human cystic echinococcosis in Egypt

We performed a retrospective study to determine annual clinical incidence of human cystic echinococcosis [CE] in 14 Egyptian hospitals between January 1997 and December 1999. From 492 353 records examined, 133 [0.027%] new human CE cases were recorded. Of these, 50 [37.6%] were from Alexandria and Matrouh hospitals, 33 [24.8%] from Giza Chest Hospital and 50 from other regions. Matrouh governorate had the highest annual clinical incidence [1.34-2.60 per 100 000] followed by Giza governorate [0.80-1.16 per 100 000]. About a third of those affected were aged </= 20 years. Liver and lungs were the organs most affected. Although human CE is of low endemicity in Egypt, it may-represent a public health concern in Matrouh and Giza governorates

A longitudinal study of schistosome intermediate host snail populations and their trematode infection in certain areas of Egypt.

Seasonal variation of Biomphalaria alexandrina and Bulinus truncatus populations and their infection rates with schistosome and other trematode cercariae were studied longitudinally in four water courses located in Giza and Faiyoum Governorates. Abundance of both species varied from year to year and according to the type of habitat. The mean prevalence of Schistosoma mansoni in Biomphalaria was 0.29%, that of S. haematobium in Bulinus was 1.36%. Seasonal variations of age structure of the 2 vector snails were monitored throughout the survey period. Infection rates with schistosome and other trematodes among Bulinus and Biomphalaria increased with the increase in snail size. Data suggest the occurrence of an antagonistic interaction between schistosome and non-human cercariae, especially echinostome, in infected snails.

Lymphatic filariasis in the Eastern Mediterranean Region: current status and prospects for elimination.

Lymphatic filariasis (LF) represents a major public health problem in tropical and subtropical regions of the world. The disease is endemic or suspected in several countries of the Eastern Mediterranean Region. Recent advances in diagnosis and therapy led the World Health Assembly to pass a resolution in 1997 calling for "the elimination of lymphatic filariasis as a public health problem." The elimination strategy is based on rounds of mass drug administration of an annual single-dose of combined drug regimens for 5-6 consecutive years. Subsequent steps included formation of a Regional Programme Review Group to orient national LF control programmes towards the concept of elimination, provide advice, review each national plan of action and review annual reports. To date, Egypt and the Republic of Yemen have active national LF elimination programmes, however, elimination activities in the Republic of Yemen are still restricted to certain identified endemic regions. Other countries in the Region are on their way to verifying the situation and if LF is proved to be endemic, will start mapping endemic localities. This review sheds light on the status of LF elimination activities in the Region and highlights some of the major accomplishments.

Filariasis elimination in Egypt: impact of low microfilaraemics as sources of infection for mosquitoes.

The elimination strategy for lymphatic filariasis aims at reducing blood microfilaraemia to levels at which vector transmission cannot be sustained. We aimed to determine whether patients with pre-treatment low or ultra-low microfilaria (MF) counts could be a reservoir of infection after mass drug administration (MDA) with a combined regimen. Laboratory-reared mosquitoes were fed on 30 volunteers after 2 rounds of MDA. Microfilaria uptake, infectivity rates and number of Wuchereria bancrofti L3 per mosquito were assessed. One year after MDA-1, 6 subjects transmitted MF, but up to 9 months after MDA-2 transmission failed. Six months after MDA-2 > 90% had clear MF smears and either failed to transmit MF or transmitted MF that did not develop to L3. We conclude that the transmission cycle is seriously weakened after MDA-2.

Filariasis elimination in Egypt: impact of low microfilaraemics as sources of infection for mosquitoes

The elimination strategy for lymphatic filariasis aims at reducing blood microfilaraemia to levels at which vector transmission cannot be sustained. We aimed to determine whether patients with pre-treatment low or ultra-low microfilaria [MF] counts could be a reservoir of infection after mass drug administration [MDA] with a combined regimen. Laboratory-reared mosquitoes were fed on 30 volunteers after 2 rounds of MDA. Microfilaria uptake, infectivity rates and number of Wuchereria bancrofti L3 per mosquito were assessed. One year after MDA-1, 6 subjects transmitted MF, but up to 9 months after MDA-2 transmission failed. Six months after MDA-2 > 90% had clear MF smears and either failed to transmit MF or transmitted MF that did not develop to L3. We conclude that the transmission cycle is seriously weakened after MDA-2

Lymphatic filariasis in the Eastern Mediterranean Region: current status and prospects for elimination

Lymphatic filariasis [LF] represents a major public health problem in tropical and subtropical regions of the world. The disease is endemic or suspected in several countries of the Eastern Mediterranean Region. Recent advances in diagnosis and therapy led the World Health Assembly to pass a resolution in 1997 calling for "the elimination of lymphatic filariasis as a public health problem." The elimination strategy is based on rounds of mass drug administration of an annual single-dose of combined drug regimens for 5-6 consecutive years. Subsequent steps included formation of a Regional Programme Review Group to orient national LF control programmes towards the concept of elimination, provide advice, review each national plan of action and review annual reports. To date, Egypt and the Republic of Yemen have active national LF elimination programmes, however, elimination activities in the Republic of Yemen are still restricted to certain identified endemic regions. Other countries in the Region are on their way to verifying the situation and if LF is proved to be endemic, will start mapping endemic localities. This review sheds light on the status of LF elimination activities in the Region and highlights some of the major accomplishments

Development and standardization of a rapid, PCR-based method for the detection of Wuchereria bancrofti in mosquitoes, for xenomonitoring the human prevalence of bancroftian filariasis.

PCR has recently been studied as a promising tool for monitoring the progress of efforts to eliminate lymphatic filariasis. PCR can be used to test concurrently at least 30 pools, with as many as 40 mosquitoes in each pool, for the presence of filarial larvae. The SspI PCR assay for the detection of Wuchereria bancrofti DNA in pools of mosquitoes has been used since 1994 in a variety of laboratories worldwide. During that time, the original assay has been modified in these different laboratories and no standardized assay currently exists. In an effort to standardize and improve the assay, a meeting was held on 15-16 November 2001, at Emory University in Atlanta, with representatives from most of the laboratories currently using the assay. The first round of testing was designed to test the four most promising methods for DNA extraction from pools of mosquitoes. Two of the four methods stood out as clearly the best and these will be now optimised and evaluated in two further rounds of testing.

Field application of PCR-based assays for monitoring Wuchereria bancrofti infection in Africa.

Approximately 50 million people in Egypt and sub-Saharan Africa have bancroftian filariasis and together they represent about a third of all cases of lymphatic filariasis (LF) world-wide. Currently, the Global Programme to Eliminate Lymphatic Filariasis, which was launched by the World Health Organization (WHO) in 1998, is largely based on repeated annual cycles of mass drug administration (MDA) to endemic populations. Also, some countries, including Egypt, are taking steps to improve LF vector-control interventions, to break the transmission cycle more effectively than is achievable with MDA alone. New tools and strategies for monitoring and evaluating elimination campaigns are needed. The last 20 years have witnessed dramatic advances in the diagnosis of LF for epidemiological purposes. The recent introduction and development of molecular technologies have moved parasite-detection systems from traditional methods (that are labour-intensive, tedious and often impractical) to improved PCR-based assays that have considerable potential for field use. The present article highlights the strengths and limitations of the PCR-based assays when used to detect filarial infections in mosquitoes (particularly for the xenomonitoring of elimination campaigns).

Infection induces antibodies against the cercarial secretions, but not against the cercarial elastases of Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum and Trichobilharzia ocellata.

Cercarial secretions from different species of the parasite Schistosoma and from Trichobilharzia ocellata contain a proteolytic activity, cercarial elastase, which was demonstrated by a 30 kDa band in gelatin gels. Sera of patients infected with Schistosoma mansoni, Schistosoma haematobium or Schistosoma japonicum contain immunoglobulin G which react in ELISA with cercarial secretions from all schistosomes and cross-react among the different parasite species. In Western blots, however, infection sera from patients, as well as heavily infected mice or rabbits, did not react with a 30-kDa protein. Moreover, when sections from infected snails (Biomphalaria, Bulinus and Lymnaea) were analysed by immunofluorescence using the same infection sera, only the tegument of the developing cercariae was recognized, but not the acetabular glands. In contrast, when antisera against purified cercarial elastase from either S. mansoni or S. haematobium were tested with sections of infected Biomphalaria or Bulinus, fluorescence was strong in the preacetabular glands of the cercariae of either species, but undetectable with the tegument. Cross-reactivity of both antisera extended to T. ocellata-infected Lymnaea, but not to S. japonicum-infected Oncomelania. In conclusion, although immunization with purified cercarial elastase results in antibody production, the enzyme does not induce an apparent antibody response following natural infection.

Detection of Wuchereria bancrofti in mosquitoes by the polymerase chain reaction: a potentially useful tool for large-scale control programmes.

Focally endemic bancroftian filariasis is targeted for elimination in the Nile delta of Egypt. Improved methods are needed for identifying endemic villages to be included in the control programme and for monitoring its success. We have evaluated the performance of a polymerase chain reaction (PCR) assay in estimating Wuchereria bancrofti infection in pools of Culex pipiens (1-25 females) from 2 adjacent villages with high (El Qolzom, 10.8%) and low (Kafr Shorafa, 2.1%) prevalence rates of human filariasis. This assay detects a repeated sequence in W. bancrofti deoxyribonucleic acid (DNA). Mosquitoes resting within houses were captured by aspiration and pooled by house. Houses were classified as positive or negative for human filarial infection based on night blood examinations of residents. The assay detected parasite DNA in mosquitoes from 60% of 25 infected houses and 24% of 25 uninfected houses. PCR processing of mosquitoes caught within houses of unknown filariasis infection status (44 in El Qolzom, 37 in Kafr Shorafa) identified 31.8% and 8.1% of houses, respectively, as containing infected mosquitoes. These results support the validity of the PCR assay for evaluating filarial prevalence in different villages. C. pipiens collected outdoors in dry ice-baited traps and tested by PCR (266 in Qolzom, 82 in Kafr Shorafa) did not contain parasite DNA. Pools of female mosquitoes (296 in Qolzom, 240 in Kafr Shorafa) captured in oviposition traps were also negative. We concluded that the PCR based assay is a powerful epidemiological tool that can be used for evaluating W. bancrofti infection in villages in the Nile delta and for monitoring the application of control programmes in filariasis endemic areas.

Evaluation of a PCR-ELISA to detect Wuchereria bancrofti in Culex pipiens from an Egyptian village with a low prevalence of filariasis.

The programmes for the elimination of bancroftian filariasis that have been implemented in the Nile delta of Egypt are expected to lead to substantial reductions in filarial loads in the treated populations. Better methods than those currently available are needed for monitoring the efficacy of these and similar efforts at intervention. A PCR-ELISA was therefore evaluated as an epidemiological tool for the detection of the Wuchereria-bancrofti-specific SspI repeat in pools of Culex pipiens collected in a village with a low prevalence of filarial infection in its human residents (2.1%). Indoor-resting mosquitoes were collected by aspiration from 114 randomly selected houses (during one to nine visits/house) and separated into 673 pools, each of which held the mosquitoes collected during one night from one house. Although 18 (2.7%) of the pools showed PCR inhibition and had to be excluded, filarial DNA was detected, using the PCR-ELISA, in 91 (13.9%) of the 655 remaining mosquito pools. The minimum prevalence of W. bancrofti infection in the mosquitoes caught (assuming one infected mosquito/positive pool) was 2.8%. The mean (S.D.) number of mosquitoes/pool did not vary significantly between positive [5.5 (3.4)] and negative [4.9 (3.5)] pools. The assay detected parasite DNA in mosquitoes from 19.3% of 114 houses when only the first visit was considered and from 73.9% of the 88 houses visited more than once. The PCR-ELISA yielded results comparable with those of the regular PCR-SspI assay. The latter assay is recommended for the routine examination, in laboratories in endemic areas, of mosquito pools from randomly selected houses, as the ELISA component of the PCR-ELISA is exceedingly time-consuming, expensive and requires special equipment.

Polymerase chain reaction assay based on a highly repeated sequence of Schistosoma haematobium: a potential tool for monitoring schistosome-infested water.

We have cloned from Schistosoma haematobium genome a repeated sequence, the DraI repeated sequence, which consists of tandemly arranged 121-bp-long units and which is highly abundant (approximately 15% of the S. haematobium genome). By these features, the DraI repeat is similar to the Sm1-7 sequence of Schistosoma mansoni previously described by us. However, their nucleotide sequences are profoundly different. Polymerase chain reaction (PCR) primers were designed on the basis of the DraI sequence information and were used in a PCR assay by which as little as 10 fg of schistosomal DNA as well as individual cercariae were detected. The DraI repeat cross-hybridized with DNA from Schistosoma bovis, Schistosoma magrebowiei, Schistosoma mattheei, Schistosoma curassoni, and Schistosoma intercalatum, but not with DNA from S. mansoni nor from Trichobilharzia ocellata and Echinostoma sp. A potential value of this PCR assay is suggested for monitoring free-living cercariae and infected snails only in bodies free of cross-hybridizing species.

Studies on the molluscicidal and larvicidal properties of Solanum nigrum L. leaves ethanol extract.

Toxicological studies on three ethanol extract preparations of Solanum nigrum L. leaves were made on Biomphalaria alexandrina. Extract (A), made by soaking leaves powder over night in cold 70% ethanol, has the highest activity, (LC50 3.37 mg/L within 24 hr). This extract also showed larvicidal activity against larvae of two mosquito species, Aedes caspius and Culex pipiens, (LC50 51.29 and 125.89 mg/L within 24 hr, and 21.38 and 38.11 mg/L within 48 hr, respectively). Sunlight, pH, and turbidity did not affect the activity of this extract, but the molluscicidal activity seems to be correlated with the increase of temperature. The concentrated extract (1000 mg/L) can be stored at room temperature for six months without any change in its activity, but diluted solutions of this extract lost their activity after four weeks.

Human antibody responses to Wuchereria bancrofti infective larvae.

Human IgG antibody responses to Wuchereria bancrofti third stage infective larvae (L3) surface and somatic antigens were studied by indirect immunofluorescence (IFA) and immunoblot with endemic Egyptian sera (n = 115) with the aim of identifying targets of protective immunity. Human sera variably recognized 14 major bands in L3 by immunoblot. The statistical significance of group differences in antibody prevalence was assessed by the chi-squared test. Children and young adults (aged 10-20 years) tended to have antibodies to more L3 somatic antigens than older adults, with significant differences for bands at 66, 60 and 5 kDa. Infected subjects had more consistent antibody responses to antigens at 55, 50 and 6 kDa than endemic normal subjects with negative serum filarial antigen tests, who are presumed to be uninfected. A 5 kDa antigen was preferentially recognized by the latter group. Antibodies to L3 surface antigens were equally prevalent in uninfected children (75%) and adults (90%) but less prevalent in people with microfilaremia (38%) than in amicrofilaremic subjects with or without filarial antigenemia (81%) (P < 0.001). IFA-positive sera showed significantly enhanced recognition of antigens at 66, 40 and 14 kDa in immunoblots relative to IFA-negative sera. Additional studies are needed to further characterize antigens identified in this study and to establish whether they are indeed targets of protective immunity in humans.