Medhat A. Darwish
Ain Shams University
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Transactions of The Royal Society of Tropical Medicine and Hygiene | 1983
Medhat A. Darwish; Harry Hoogstraal; Thomas J. Roberts; Ismat P. Ahmed; Ferial Omar
Complement-fixation test reactions to eight viruses of the family Togaviridae were studied in 372 serum samples (157 rodents, 172 domestic animals, 43 humans) from Pakistan. Antibodies to each tested virus were detected. The highest over-all prevalence rates were for West Nile (WN) (7.8%), Japanese encephalitis (JE) (3.2%) and Zika (ZIKA) (2.4%) viruses, followed by Sindbis (SIN), Chikungunya (CHIK), Uganda S (UGS) and Royal Farm (RF) viruses (1.6 to 1.3%). One human serum (male, age 58 years) reacted with Dengue-1 (DEN) virus antigen (titre 1:32). Antibodies to each virus except RF were detected in human sera; antibodies to RF virus were detected only in rodent and domestic animal sera. The roles of rodents in the epidemiology of WN, JE and ZIKA viruses should be investigated. At least six of these eight viruses cause fevers in humans (fevers of unknown origin comprise about one third of the febrile episodes recorded in Pakistan).
The Lancet | 1993
R.R. Arthur; S.E. Cope; B.A. Botros; R.G. Hibbs; I.Z.E. Imam; M.S. El-Sharkawy; S. Oun; J.C. Morrill; Robert E. Shope; Medhat A. Darwish
Rift Valley fever (RVF) has been recorded in man and in domestic animals in Egypt after a 12-year absence. Human infections were first noted in the Aswan Governorate in late May, 1993. Only cases of ocular disease, an infrequent and late manifestation, were reported. Of 41 cases, 35 were tested serologically and 27 (77%) had RVF virus-specific IgM antibodies. An estimated 600-1500 infections occurred in the region. Abortions in cattle and buffalo were seen concurrently and antibodies to RVFV were present in 39% of domestic livestock, presumably unvaccinated. RVFV was isolated from an aborted water buffalo fetus.
BMC Infectious Diseases | 2002
Malla R. Rao; Abdollah Naficy; Medhat A. Darwish; Nebal M Darwish; Enrique Schisterman; John D. Clemens; Robert Edelman
BackgroundHepatitis C virus (HCV) infection and schistosomiasis are major public health problems in the Nile Delta of Egypt. To control schistosomiasis, mass treatment campaigns using tartar emetic injections were conducted in the 1960s through 1980s. Evidence suggests that inadequately sterilized needles used in these campaigns contributed to the transmission of HCV in the region. To corroborate this evidence, this study evaluates whether HCV infections clustered within houses in which household members had received parenteral treatment for schistosomiasis.MethodsA serosurvey was conducted in a village in the Nile Delta and residents were questioned about prior treatment for schistosomiasis. Sera were evaluated for the presence of antibodies to HCV. The GEE2 approach was used to test for clustering of HCV infections, where correlation of HCV infections within household members who had been treated for schistosomiasis was the parameter of interest.ResultsA history of parenteral treatment for schistosomiasis was observed to cluster within households, OR for clustering: 2.44 (95% CI: 1.47–4.06). Overall, HCV seropositivity was 40% (321/796) and was observed to cluster within households that had members who had received parenteral treatment for schistosomiasis, OR for clustering: 1.76 (95% CI: 1.05–2.95). No such evidence for clustering was found in the remaining households.ConclusionClustering of HCV infections and receipt of parenteral treatment for schistosomiasis within the same households provides further evidence of an association between the schistosomiasis treatment campaigns and the high HCV seroprevalence rates currently observed in the Nile delta of Egypt.
The Lancet | 1995
Michel Jadoul; Alberto Frosi; MariaClotilde Ragni; Leonardo Salvaggio; Silvia Vezzoli; Francesco Vezzoli; Medhat A. Darwish; Rifky Faris; John D. Clemens; Malla R. Rao; Robert Edelman
Using molecular biological techniques, a viral genome was cloned from the serum of a chimpanzee infected with non-A, non-B (NANB) hepatitis. The virus was designated the hepatitis C virus (HCV) and has been shown to be the major causative agent of NANB hepatitis. Since then, HCV has emerged as a major cause of chronic liver disease with a prevalence of 1.8% in the United States. Studies of HCV have been hampered by the lack of an easy animal or tissue culture model. HCV has been classified as the third genus of the Flaviviridae family, which, together with pestiviruses and flaviviruses, are single-stranded RNA viruses with a positive polarity and share a similar genomic structure and organization. Immunohistochemical studies have shown that HCV antigens are widespread in the liver within the cytoplasm of hepatocytes and also within the infiltrating lymphoid aggregates. HCV appears to be the dominant factor associated with hepatocellular carcinoma (HCC) in areas with intermediate rates of HCC, whereas hepatitis B virus is the dominant factor in areas with higher rates of HCC. Great strides have been made in understanding the virology and immunology of the human immunodeficiency virus (HIV), and therapeutic regimens have recently achieved suppression of viral replication to undetectable levels. Therapeutic trials for NANB hepatitis using interferon-alpha were initiated in the 1980s before diagnostic tests for HCV were available. The development of infectious cDNA clones is a great stride forward as it will permit the use of a standard infectious inoculum without quasispecies.
Toxicon | 1973
A.H. Mohamed; Medhat A. Darwish; M. Hani-Ayobe
Abstract A monovalent specific antivenin was prepared in horses against the Egyptian cobra (Naje haje) venom; using bentonite as an adjuvant. One ml of the serum tested at the end of the six-month program neutralized 64 ld 50 and protected against 53 ld 50 in mice. Cross immunological studies were carried out with five elapid, six viperid and one crotalid venoms. The serum proved effective in neutralization of and protection against these venoms. Precipitation reaction lines were obtained using the Ouchterlony technique, with most of the venoms. Identity patterns were established between venoms of N. haje, N. nigricollis, N. flava, N. naja, Walterinnesia aegyptia of the Elapidae as well as those of Echis carinatus and Ethiopian N. haje. Partial identity with the two vipers Cerastes cerastes and Cerastes vipera and nonidentity with Echis coloratus venom. Weak or no reactions were given with the Ethiopian Bitis lachesis, Bitis gabonica and the Japanese Trimeresurus flavoviridis.
Toxicon | 1973
A.H. Mohamed; Medhat A. Darwish; M. Hani-Ayobe
Abstract Polyvalent antivenin was prepared against the Egyptian snake venoms Naja haje, N. nigricollis, Cerastes cerastes and C. vipera , and tested by neutralization and immunodiffusion tests. The antivenin was of high potency against the Egyptian snake venoms, especially C. cerastes and C. vipera , followed by Echis carinatus, E. coloratus, N. haje, N. nigricollis and Walterinnesia aegyptia . The titre against the African and Indian cobra venoms N. nivea, N. haje (Ethiopian) and N. naja was lower, while poor or no effect was shown against Bitis arietans, B. gabonica and Trimeresurus flavoviridis venoms. The polyvalent serum prepared in horses not previously immunized, was comparable to sera obtained by using horses, which were previously immunized against a single venom. However, the latter sera, still maintained their higher titre against the original sensitizing venom. Comparison of polyvalent and monovalent N. nigricollis antivenins, revealed that while the polyvalent serum was of better effectiveness against the Egyptian viper venoms especially cerastes venoms, more protection was provided by the monovalent serum against the naja venoms.
Toxicon | 1973
A.H. Mohamed; Medhat A. Darwish; M. Hani-Ayobe
Abstract Monovalent Naja nigricollis antivenin was prepared in horses using venom adsorbed to bentonite (first three injections) followed by increasing doses (up to 50 mg) of unmodified venom. The serum (1 ml) neutralized 51 ld 50 s of its homologous venom. Good neutralizing capacity (30–50 ld 50 s per ml) was also shown against venoms of N. haje , N. nivea , N. naja , Walterinnesia aegyptia , Cerastes cerastes and Cerastes vipera as well as Echis carinatus venom. For all these venoms, identity patterns, complete or partial, were established using Ouchterlonys technique. Moderate neutralization (22 ld 50 s per ml) was shown against Echis coloratus venom which gave a nonidentity pattern. Low neutralization (10 ld 50 s per ml) was observed with venoms of Bitis arietans , B. gabonica and Trimeresurus flavoviridis ; all these venoms showing very weak or no precipitation lines with Naja nigricollis antivenin.
Toxicon | 1974
A.H. Mohamed; Medhat A. Darwish; M. Hani-Ayobe
Abstract A monovalent C. cerastes antivenin was prepared in horses. At the end of the immunization course 1 ml of serum neutralized 92 ld 50 of its homologous venom. Cross neutralization was evident against Cerastes vipera venom (53 ld 50 s per ml serum), but was low against the venoms of Echis carinatus, Bitis gabonica, B. arietans. Dendroaspis polylepis, D. angusticeps, Naja haje, N. nigricollis, N. nivea, N. naja and W. aegyptia (8–20 ld 50 per ml) and there was no protection against T. flavoviridis venom. Precipitation bands obtained by Ouchterlony immunodiffusion studies, gave comparable results showing stronger reaction against the venoms of C. cerastes and C. vipera and weaker reactions against the other venoms.
American Journal of Tropical Medicine and Hygiene | 1993
Medhat A. Darwish; Tahani A. Raouf; Perween Rushdy; Niel T. Constantine; Malla R. Rao; Rober Edelman
American Journal of Tropical Medicine and Hygiene | 1996
Medhat A. Darwish; Rifky Faris; John D. Clemens; Malla R. Rao; Robert Edelman