Mosquito identification and molecular xenomonitoring of lymphatic filariasis in selected endemic areas in Giza and Qualioubiya governorates, Egypt

Lymphatic filariasis is a vector-borne health problem that has been focally endemic in Egypt for centuries. The chief vectors of transmission are Culicinae species. Control measures in the form of mass drug administration of DEC citrate treatment have been implemented in Nile delta for almost a decade. This study aimed to identify the prevalent mosquito species in endemic areas in Giza and Qualioubiya governorates and to monitor Wuchereria bancrofti infection by detecting the parasite DNA in collected mosquitoes. Adult mosquitoes were collected using light traps hung indoors. Microscopic examination was performed to identify and examine the morphologic characters of mosquitoes. Female Culex mosquitoes were subjected to semi-nested PCR to detect filarial DNA targeting repetitive DNA sequences [pWb12 repetitive region] specific for W.bancrofti

The results revealed 3 species of mosquitoes Culex pipiens, Culex pusillus and Culex quinquefasciatus with the predominance of Culex pipiens [85.7%]. Wuchereria bancrofti DNA was not detected in any of the collected mosquito pools. With the progress of elimination programme in Nile Delta, follow up studies with larger sample size are recommended as the predominance of Culex pipiens the main lymphatic filariasis vector remains a risk of transmission in such areas

Elisa-based coproantigen in human strongyloidiaisis: a diagnostic method correlating with worm burden

In order to overcome the false negative diagnosis of strongyloidiasis in the absence of rhabditiform larvae in stools, an ELISA-based Strongyloides stercoralis-spicific coproantigen detection assay in stools of infected patients was evaluated. In a sandwich ELISA, a rabbit hyperimmune serum against S. ster-coralis ES [excretory/secretory] adult antigen succeeded in capturing S. ster-coralis coproantigen from infected patients and did not react with copro-antigens prepared from the stool samples of patients infected with Schistosoma mansoni, Fasciola gigantica and Capillaria philippenensis. Coproantigen was able to detect anti-S. stercoralis IgG antibodies in sera of infected patients at the same OD level as produced with S. stercoralis E/S worm antigen using an indirect ELISA did not cross-react with sera from patients with S. mansoni, F. gigantica and C. philippenensis. S. stercoralis coproantigen detection proved a sensitive, simple, reliable and inexpensive ELISA-based, and an alternative to coproscopical methods in copropositive [with larvae in stool] and copro-negative [without larvae in stool] stool samples. Fecal ELISA showed a positive relationship between copro-Ag and worm burdens, and considered a starting point for the development of species-specific copro-immunological diagnostic assays using monoclonal antibodies and dipstick technology

Nocturnal activity and biting rhythm of sand flies [diptera; psychodidae] in Al-Agool, Al-Madinah Al-Munawarah, Saudi Arabia

The study of phlebotomine sand flies activity and biting rhythms are of vital importance determining the period of maximum risk of Leishmania infection, prevention of transmission, and in successful control. This study was carried out aiming to reach a better understanding of the phlebotomine sandflies activity and biting rhythms in Al-Agool village, Al-Madinah Al-Munawarah, Saudi Arabia, an area of zonootic cutaneous leishmaniasis. Three collection methods were used to collect sand flies; CDC miniature light traps, sticky traps and aspirator collection off human bait, for six nights [12 hours each] in May and June, 2007. Four species were detected; Phlebotomus papatasi, P sergenti, Sergentomyia cyldei and S. antennata. P. papatasi was found to be the most abundant species [81%]. Sticky traps sampled the greater number of phlebotomine flies [43.4%], followed by light traps [31%], catching all of the 4 collected species. Human bait sampled 25.6%, only Phlebotomus species were collected by this method. Both sexes of collected sand flies displayed nocturnal activity with different patterns; the females nocturnal activity was repuscu1ar, exhibiting two peaks of activity, a larger one after dusk and a smaller one before dawn, whereas t of males was clearly nocturnal. Also, females biting rhythms follow that of nocturnal activity. This poses a greater risk for humans to be bitten and infected by the 'various sand fly-borne pathogens. This is especially important in intra-domiciliary settings during the night, in particular, after dusk and before dawn

study on culex species and culex transmitted diseases in Al-Madinah Al-Munawarah, Saudi Arabia

Culex mosquitoes transmit bancroftian filariasis and arboviruses as West Nile Virus in the Middle East including Saudi Arabia. However, the prevalent Culex species in Al-Madinah region have not been reported and their role in disease transmission remains to be clarified. This work aimed to investigate the role of Culex in transmission of Wuchereria bancrofti, West Nile virus, Saint Louis encephalitis and Eastern Equine encephalitis in Al-Madinah, Saudi Arabia. Also, it was done to document the prevalent Culex species and to shed light on their bionomics and habits. Culex mosquitoes were collected using spray sheets and CDC light traps with CO2 release from July 2007 till June 2008. Also, Culex larvae were collected for 8 months during that period. Culex seasonal distribution and bionomics were documented and taxonomical identification was done. Females were dissected and microscopically examined for filarial stages. In addition, they were screened by the Vec-Test for West Nile virus, Saint Louis encephalitis and Eastern Equine encephalitis. A total of 3.6% human rooms and 4.7% of animal sheds were positive for Culex; more in the period of January-June 2008, compared to July-December 2007. Seven Culex species were found, two of which were recorded for the first time in the region; C. duttoni and C. decens. C. pipiens and C. quinquefasciatus were the most abundant; 59.3% of collected adults were C. pipiens, while C. quinquefasciatus constituted 22.1%. As for collected larvae, C. pipiens constituted 60% of them, whereas C. quinquefasciatus totalled 20%. Only C. pipie/Is was found to harbor West Nile Virus. In contrast, no other viruses or W bancrfoti stages were detected in the examined mosquitoes. There is a potential danger of the transmission of West Nile Virus in Al-Madinah especially by C. pipiens. Also, the possibility of future transmission of W. bancrofti, and the establishment of new endemic foci of bancroftian filariasis in the region, couldn't be overruled

Early post-treatment immunoglobulin profile in human schistosomiasis

In a trial at determining the most relevant immunoglobulin isotype that could reflect success of praziquantel treatment, an ELISA using soluble egg antigen [SEA] was applied on sera of Egyptian patients suffering from active intestinal schistosomiasis without hepatic complications determining the levels of IgE, IgA, IgM, IgGl, IgG2, IgG3 and IgG4 raised against the SEA, bot0h pre- and early post-treatment. The positive results obtained to all anti-SEA immunoglobulin isotypes before treatment support the usefulness of this technique in the diagnosis of schistosomiasis. Except for IgG3 subclass, a statistically significant correlation was found between egg output-reflecting intensity of infection-and the different immunoglobulin levels, especially anti-SEA IgG4. When repeating the assay 5-6 months after treatment, the immunoglobulin levels showed either a rise [in case of IgE] or a drop [in case of IgA, IgM and IgG1-4], all of statistical significance; yet IgG1-4 were still positive. So, ELISA could not give a definite indication of cure after anti-bilharzial treatment. IgE, IgG2 and IgG4 were revealed to be the most significant immunoglobulin isotypes at the post-treatment level, both statistically and due to their implications on resistance/susceptibility to re-infection and also due to the correlation of IgG4 with the tendency to develop periportal fibrosis. Conclusively, although not having defined a particular Ig isotype as marker for cure, it exposed the urge for early post-treatment determination of IgE and IgG4 isotypes which could serve as markers for picking up high risk patients susceptible to re-infection or liable to develop bilharzial periportal fibrosis and who might benefit from a second course of specific treatment

Evaluation of capillaria philippinensis coproantigen in the diagnosis of infection

In order to overcome the false negative diagnosis of infection with C. philippinensis in the absence of eggs in stool, coproantigen prepared from the stools of infected patients was evaluated serologically. This antigen was able to detect anti-Capillaria antibodies in the sera of infected cases at the same OD level produced with Capillaria crude worm antigen using indirect ELISA technique. C. Philippinensis coproantigen did not cross-react with the sera from patients with Schistosomiasis mansoni, Fascioliasis or Strongyloidiasis at 1:00 serum dilution. Laboratory-prepared hyperimmune sera versus crude worm antigen of C. philippinensis succeeded in capturing Capillaria antigen prepared from the stools of infected patients and did not cross-react with the coproantigens prepared from the stool samples of cases infected with S. Mansoni or Fasciola using sandwich ELISA technique

Evaluation of parasep [faecal parasite concentrator] for detection of Giardia lamblia in faeces

This study was carried on 168 patients suspected to be infected with Giardia lamblia. They were all subjected to direct stool microscopic examination, formol-ether concentration and by Parasep [fecal parasite concentrator]. The results showed that 14.3% of the patients were positive for giardiasis by Parasep 10.7 were positive for giardiasis by formol-ether concentration and 5.35% of the cases were positive by direct stool microscopic examination. The results showed that the use of Parasep is an effective and convenient mean for the detection of G. lamblia cysts in feces with the disadvantage of highly cost-benefit taking into consideration that the microscopic examination is the gold standard of giardiasis