DNA sequence encoding the amino-terminal region of the human c-src protein: implications of sequence divergence among src-type kinase oncogenes.

We sequenced the 5'-coding region of the human c-src gene, exons 2 through 5, corresponding to one-third of the human c-src protein consisting of 536 amino acids. Sequence analysis of the src type of protein kinases revealed that the amino-terminal region encoded by exon 2 contains sequences specific for the src proteins and raised the possibility that this region is involved in the recognition of a src-specific substrate(s) or receptor(s).

DNA sequence organization and transcription of the chicken genome.

A new approach has been used to examine DNA sequence organization in the chicken genome. The interspersion pattern was determined by studying the fraction of labelled DNA fragments of different lengths that hybridized to an excess of short chicken repeated DNA sequences. The results indicate that chicken DNA has a pattern of sequence organization quite different than the standard 'Xenopus' or 'Drosophila' patterns. Two classes of unique sequences are found. One, 34% of the genome, consists of unique sequences approx. 4 kb long interspersed with repeated sequences. The second, non-interspersed fraction, 38% of the genome, consists of unique sequences found in long tracts, a minimum of approx. 22 kb in length. In an attempt to determine whether a relationship exists between DNA sequence organization and the distribution of structural genes we have isolated chicken DNA sequences belonging to different interspersion classes and tested each for the presence of structural genes by hybridization to excess poly(A)+ mRNA. Sequences complementary to poly(A)+ mRNA can be found with approximately the same frequency in both the non-interspersed fraction of the genome and a repeat-contiguous fraction enriched for interspersed sequences.

Association of BK virus with failure of prophylaxis against hemorrhagic cystitis following bone marrow transplantation.

PURPOSE: Hemorrhagic cystitis (HC) after bone marrow transplantation (BMT) has been ascribed to cyclophosphamide metabolites. HC has also been associated with excretion of the BK type of polyomavirus. The relative contributions of cyclophosphamide metabolites and BK virus in the development of HC following BMT are unknown. PATIENTS AND METHODS: We conducted a randomized trial to compare mesna with forced diuresis for prophylaxis against HC in 147 BMT recipients. We studied the association of BK virus with HC in 95 consecutive BMT recipients by prospectively monitoring urinary excretion of BK virus using polymerase chain reaction amplification of viral gene sequences. RESULTS: HC occurred in 37 of 147 (25.2%) transplant recipients. The incidence of HC was similar in patients given mesna (26.8%, 19 of 71) or forced diuresis (23.7%, 18 of 76), and in recipients of allogeneic (27.2%, 18 of 64) or autologous marrow (22.9%, 19 of 83). The incidence of HC was unrelated to primary disease, preparative regimen, or occurrence of graft-versus-host disease (GVHD). Excretion of BK virus was demonstrated in 50 of 95 patients (52.6%); 38 patients (40%) had persistent BK viruria (> or = two consecutive positive samples). HC occurred in 19 of 38 patients (50%) with persistent BK viruria, in one of 12 (8.3%) with only a single urine sample positive for BK virus, and in none of 45 who did not excrete BK virus (P < .0001). Shedding of BK virus also had a strong temporal correlation with onset of HC (r = .95). CONCLUSION: Mesna and forced diuresis are equally effective in abrogating the urothelial toxicity of preparative regimens for BMT. Since HC after BMT is virtually always associated with persistent BK viruria, strategies aimed at the prevention or elimination of viruria in BK seropositive recipients are warranted.

Combination antibiotic therapy in staphylococcal endocarditis. The use of methicillin sodium-gentamicin sulfate therapy.

The addition of gentamicin therapy in a case of S aureua endocarditis, in which the response to methicillin therapy alone was unsatisfactory, resulted in clinical improvement, enhanced serum bactericidal activity, and a bacteriologic cure. Gentamicin and methicillin were synergistic in vitro. Since the mortality in staphlococcal endocarditis remains exceedingly high, we suggest that the combination of a cell wall active antibiotic, such as methicillin, and an aminoglycoside may prove to be effective alternate theraphy for this disease.

Comparison of two methods for same-day identification of Enterobacteriaceae.

Two commercial methods, API 20E (as modified for same-day enterobacterial identification) and Micro-ID, were evaluated for ability to provide useful same-day information of 368 clinically isolated Enterobacteriaceae. Organisms included Escherichia coli (54), Shigella (7), Edwardsiella tarda (1), Salmonella enteritidis (10), Citrobacter (30), Klebsiella (55), Enterobacter (68), Hafnia alvei (2), Serratia (33), Proteus (64), Morganella morganii (24), Providencia (18), and Yersinia enterocolitica (2). Methods were those of manufacturers without supplemental tests. API at five hours identified 78.5% of strains to species, 9.5% to genus only, 10.1% as part of a spectrum of identifications (SI), and 1.9% incorrect. Micro-ID at four hours yielded 90.0% correct identification to species and 3.3% to genus only, 4.0% SI, and 2.7% incorrect. API identification of many Serratia, Citrobacter, Providencia strains was to genus only; most incorrect results occurred in Serratia marcescens. Micro-ID identified most organisms to species; incorrect identifications were mainly S. marcescens and Klebsiella pneumoniae. Both systems provided excellent identification of E. coli. Both methods sacrifice a degree of accuracy that varies with the species tested, as compared to overnight systems, but both provide rapid information of potential clinical value.

Grouping of hantaviruses by small (S) genome segment polymerase chain reaction and amplification of viral RNA from wild-caught rats.

A single pair of consensus primers in the polymerase chain reaction (PCR) amplified a conserved region of the small genome segment of twenty hantavirus isolates. Isolates tested included representatives of the four recognized hantaviruses, Hantaan, Seoul, Puumala and Prospect Hill, as well as isolates from Mus musculus (Leakey), Bandicota indica (Thailand 749), and Suncus murinus (Thottapalayam). Viruses from the Nairovirus and Phlebovirus genera yielded negative results. The amplification products were 281-nucleotide pairs (np) in length, with the exception of Thottapalayam, which had an amplification product of approximately 320 np. Products of all isolates were detected by Southern hybridization with a 32P-labeled Hantaan 76-118 amplicon, while an oligonucleotide probe to a conserved region of the amplified fragment failed to detect some isolates of Seoul and Puumala viruses. Restriction endonuclease analysis allowed three groupings: Hantaan-like viruses, Seoul-like viruses, and a diverse group of patterns for the other viruses. Differences were found within the Seoul-like virus group by this method, whereas the Hantaan-like viruses were shown to be similar. RNA extracted from tissues of seropositive and seronegative rats trapped in Baltimore showed the practical application of the test. Hantavirus-specific RNA was detected in 12 (92%) of 13 seropositive rats, but not in seronegative rats. This simple method for detecting and characterizing hantaviruses has potential for epidemiologic studies and for diagnosing human hantavirus infections.

Seroprevalence survey of Egyptian tourism workers for hepatitis B virus, hepatitis C virus, human immunodeficiency virus, and Treponema pallidum infections: association of hepatitis C virus infections with specific regions of Egypt.

Blood samples from 740 Egyptian Nationals working in the tourism industry at two sites in the South Sinai governorate were screened for markers of infection with hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Treponema pallidum. Study subjects included 467 individuals from a rural seashore tourist village and 273 persons at two hotels in a well-established resort town. Subjects' ages ranged from 15 to 70 years; 99.3% were male. The prevalence of serologic markers for currently asymptomatic or past HBV infection alone was 20.7% (n = 153), of markers for past or chronic HCV infection alone was 7.4% (n = 55), and of markers for both HBV and HCV was 6.9% (n = 51). Of the 204 individuals positive for anti-HBV core antibody, 12 (5.9%) were also positive for hepatitis B surface antigen. Two individuals (0.3%) had a serologic market suggestive of an active syphilitic infection. No subject was found to be HIV-seropositive. History of prior injections and number of injections were associated with infection with HCV. Primary residence in the Nile delta and valley areas where schistosomiasis is highly endemic, was also a statistically significant risk factor for HCV, but not HBV infection.

PIP: In June 1994, in Egypt, a physician, a laboratory technician, and a recorder surveyed 740 nationals aged 15-70 years, 99.3% of whom were male, who worked in the local tourist industry of the South Sinai governorate (a rural seashore tourist village and a well-established tourist town). Researchers aimed to determine the prevalence of past or chronic infections with hepatitis B virus (HBV), hepatitis C virus (HCV), HIV, and Treponema pallidum (syphilis) in tourist workers and to identify risk factors for infection with these pathogens. Condoms were used and safer sex was practiced in about 90% of casual sexual encounters. No tourist worker tested positive for HIV-1 or HIV-2 infection. 0.3% had active syphilis. 27.6% of the tourist workers tested positive for HBV. 1.6% (5.9% of HBV-positive workers) were positive for hepatitis B surface antigen, indicating an asymptomatic HBV infection. 14.3% of all tourist workers tested positive for HCV. 6.9% tested positive for both HBV and HCV. Rural residence was a significant risk factor for HBV infection (odds ratio [OR] = 1.6; p = 0.02). Significant risk factors for HCV infection included residence in a region highly endemic for schistosomiasis (i.e., Nile delta and valley areas) (OR = 3.2; p 0.01), rural residence (OR = 2.3; p = 0.01), and more than 10 lifetime injections (OR = 2.6; p = 0.02).

Vector competence of Egyptian mosquitoes for Rift Valley fever virus.

Reintroduction of Rift Valley fever (RVF) into Egypt in 1993 raised concerns about the potential for Egyptian mosquitoes to transmit the virus. We evaluated the ability of Aedes caspius, Culex pipiens, Cx. antennatus, Cx. perexiguus, Cx. poicilipes, and Anopheles pharoensis collected in the Aswan area and Cx. pipiens collected in the Nile Delta to transmit RVF virus. All mosquito species tested were susceptible to RVF virus infection, with An. pharoensis and Ae. caspius being the most sensitive to infection. However, none of 12 An. pharoensis, including 10 with a disseminated infection, transmitted RVF virus by bite. In contrast, nearly all Cx. pipiens (87%, n = 15) and Cx. perexiguus (90%, n = 10) with a disseminated infection transmitted virus. Overall transmission rates for mosquitoes exposed to hamsters with a viremia > or = 10(7) plaque-forming units/ml were Ae. caspius, 20% (n = 5); Cx. pipiens, 7% (n = 102); Cx. antennatus, 7% (n = 30); Cx. perexiguus, 11% (n = 9); and An. pharoensis, 0% (n = 7). Based on abundance, susceptibility to infection, ability to transmit virus, and feeding behavior, Ae. caspius appeared to be the most efficient vector of the Egyptian mosquitoes evaluated. While less susceptible than Ae. caspius, Cx. pipiens, Cx. antennatus, and Cx. perexiguus were also potential vectors during this RVF outbreak in Egypt.

Prevalence of antibodies to hepatitis E in two rural Egyptian communities.

A population-based serosurvey in two rural Egyptian communities was used to assess age-specific prevalence of antibody to hepatitis E virus (anti-HEV). One community is in the Nile Delta (11,182 inhabitants; 3,997 participants) and the other in Upper Egypt (10,970 inhabitants; 6,029 participants). Samples were tested for anti-HEV with a commercial enzyme-linked immunoassay (ELISA) based on antigens derived from open reading frame (ORF)2 and ORF3. Although there was a clear difference in sensitivity among the lots of the commercial test used, it was still possible to determine the seroprevalence. The seroprevalence of anti-HEV exceeded 60% in the first decade of life, peaked at 76% in the second decade and remained above 60% until the eighth decade. Prevalence of this magnitude is among the highest reported in the world, with an age-specific pattern more similar to hyperendemic hepatitis A virus transmission than generally described. Lot-to-lot variation in the sensitivity of the commercial ELISA kit highlights a problem when comparing seroepidemiologic studies of different populations.

Dengue fever in U.S. troops during Operation Restore Hope, Somalia, 1992-1993.

Dengue fever (DF) was considered to be a potential cause of febrile illness in U.S. troops deployed to Somalia during Operation Restore Hope in 1992-1993. A prospective study of hospitalized troops with fever and a seroepidemiologic survey of 530 troops were conducted. Among 289 febrile troops hospitalized, 129 (45%) did not have an identified cause of their fever. Dengue (DEN) virus was recovered from 41 (43%) of 96 of these patients by inoculation of admission sera into C6/36 cell cultures. Thirty-nine (41%) of the isolates were identified as DEN-2 and two (2%) as DEN-3 by an indirect immunofluorescent antibody assay. An additional 18 (49%) of 37 culture-negative cases were shown by immunoglobulin M (IgM) antibody capture enzyme-linked immunosorbent assay to have anti-DEN virus antibody. All identified DF cases recovered within 1-2 weeks; no case of dengue hemorrhagic fever or shock syndrome was observed. A seroepidemiologic survey of a unit (n = 494) with 17 culture or serologically identified DF cases and a 13% attack rate of unidentified febrile illness revealed a 7.7% prevalence of anti-DEN virus IgM antibody. Failure to use bed nets was the only identified risk factor for DEN infection (adjusted odds ratio = 2.2, 95% confidence interval = 1.4-3.0). These data indicate that DF was an important cause of febrile illness among US troops in Somalia, and demonstrate the difficulties in preventing DEN infection in troops operating in field conditions.

Monovalent latex agglutination reagents for the diagnosis of nonmeningitic pneumococcal infection.

The pneumococcus is a leading cause of serious bacterial infection worldwide. Given the difficulties with available assays for the diagnosis of invasive nonmeningitic pneumococcal infection, we evaluated monovalent slide latex agglutination reagents among patients with blood culture-confirmed pneumococcal infection and control patients in Baltimore, Maryland, USA; São Paulo, Brazil; and Cairo, Egypt. Among 50 patients with invasive nonmeningitic pneumococcal infection, 23 had a positive urine test for a sensitivity of 46% (95% confidence intervals of 32% and 61%). Among 39 healthy children, 36 had a negative assay, for a specificity of 92% (95% confidence intervals of 78% and 98%). Among 80 children with pneumonia without a positive blood culture for Streptococcus pneumoniae, the specificity was 88% (95% confidence intervals of 78% and 94%). Although the assay was fairly specific, the positive predictive value using optimistic assumptions was only 73%-83%. This study suggests that this assay has a sensitivity and positive predictive value that may limit its value in some settings.

Application of an immunoperoxidase monolayer assay for the detection of arboviral antibodies.

An immunoperoxidase monolayer assay (IPMA) was adapted for the detection of antibodies to six arboviruses: three viruses within the flavivirus group (dengue 2, West Nile (WN) and yellow fever) and three in the phlebovirus group (Rift Valley fever (RVF), sandfly fever Naples and sandfly fever Sicilian). Antibody titers of homologous hyper-immune mouse ascitic fluid (HMAF) measured by IPMA were two to eight-fold less than those determined by ELISA. In tests with heterologous HMAF, cross-reactions frequently observed in ELISA, particularly in the flavivirus group, were absent in all IPMA titrations. With human serum samples tested for antibodies to RVF (n = 52) and WN (n = 90), the sensitivity of IPMA as compared with ELISA was 96 and 91%, respectively, specificity of IPMA was 100%. In addition, the IPMA format has several advantages that make it a useful alternative to ELISA for diagnosing arboviral infections under field conditions.

Hepatitis C antibody prevalence in blood donors in different governorates in Egypt.

Markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections were sought in serum samples from 2644 blood donors in 24 of Egypt's 26 governorates. Of the 2644 samples, 656 (24.8%) were shown to contain anti-HCV immunoglobulin G antibody by Abbott second generation enzyme immunoassays (EIA). Of 85 EIA-positive samples tested by recombinant immunoblot assay, 72 (85%) were positive. HCV seroprevalence in the governorates ranged from zero to 38%; 15 governorates (62%) had an HCV antibody prevalence greater than 20%, and 6 (25%) greater than 30%. Governorates with higher sero-prevalences were located in the central and north-eastern Nile river delta, and south of Cairo in the Nile river valley. Subjects from areas in and adjoining the Sinai peninsula, in the eastern and western desert, and in southernmost Egypt, had the lowest prevalence of HCV antibody. The large urban governorates of Cairo and Alexandria had antibody prevalences of 19% and 11%, respectively. A total of 39.4% subjects had evidence of HBV infection (and-HBV core antigen total antibody). HCV infections were detected more frequently in donors with markers for HBV infections than in uninfected subjects (36% versus 18%, P < 0.001).

Prevalence of hantavirus antibody in patients with chronic renal disease in Egypt.

In Egypt, the etiology of chronic renal failure (CRF) is not well defined. A hospital-based case-control study was initiated in February 1998, to determine whether hantavirus infection is involved in chronic renal disease (CRD) in Egypt. The study enrolled 350 study patients with a history of CRF and 695 matched controls with CRD due to renal calculus or renal cancer, but with normal renal functions. Sera from cases and controls were tested for anti-hantavirus IgG using ELISA with a cell-lysate antigen from Hantaan virus prototype strain 76-118. A demographic questionnaire was completed for each study participant. Five of the 350 cases (1.4%), and seven of the 695 controls (1.0%) were antibody-positive to hantavirus, with a titer > or =1:400. The difference in antibody prevalence between the study cases and the control cases was not statistically significant (P = 0.48). All antibody-positive study cases and controls had been exposed to rodents. Data indicated that in Egypt, hantavirus seroprevalence in CRD patients is low, and hantavirus infections do not appear to be a significant cause of CRF.

Epidemic dengue 2 in the city of Djibouti 1991-1992.

From October 1991 to February 1992, an outbreak of acute fever (in which thick blood films were negative for malaria) spread rapidly in the city of Djibouti, Djibouti Republic, affecting all age groups and both nationals and foreigners. The estimated number of cases was 12,000. The clinical features were consistent with a non-haemorrhagic dengue-like illness. Serum samples from 91 patients were analysed serologically for flavivirus infection (dengue 1-4, West Nile, yellow fever, Zika, Banzi, and Uganda-S), and virus isolation was attempted. Twelve strains of dengue 2 virus were isolated. Dengue infection was confirmed by a 4-fold or greater rise in immunoglobulin (Ig) G antibody in paired serum specimens, the presence of IgM antibody, or isolation of the virus. Overall, 46 of the suspected cases (51%) were confirmed virologically or had serological evidence of a recent flavivirus infection. Statistical analysis showed that the presence of a rash was the best predictor of flavivirus seropositivity. In November 1992, Aedes aegypti was widespread and abundant in several districts of Djibouti city. A serological study of serum samples collected from Djiboutian military personnel 5 months before the epidemic showed that only 15/177 (8.5%) had flavivirus antibodies. These findings, together with a negative serosurvey for dengue serotypes 1-4 and yellow fever virus performed in 1987, support the conclusion that dengue 2 virus has only recently been introduced to Djibouti.

Ebola in Africa--discoveries in the past decade.

Within the past decade, Ebola haemorrhagic fever (EHF) has been recognised for the first time in four countries. Our understanding of the epidemiology, clinical aspects, laboratory diagnosis and control measures for EHF has improved considerably as a result of the outbreaks in these countries and the re-emergence that has occurred in another. The coordinated international responses to several of the large EHF outbreaks serve as models for controlling epidemics of other communicable diseases. This report is a chronological overview of the EHF outbreaks in Africa during the past decade, including the recent epidemics in Gabon and the Republic of the Congo, and highlights new discoveries and some of the remaining challenges.

Diagnosis of progressive multifocal leukoencephalopathy by stereotactic brain biopsy utilizing immunohistochemistry and the polymerase chain reaction.

This report describes the diagnosis of progressive multifocal leukoencephalopathy (PML) in nine patients using cytopathologic and histopathologic examination of computed tomographically guided stereotactic brain biopsies in combination with immunostaining for SV-40-related antigen and the polymerase chain reaction (PCR) for the JC virus. In four patients the diagnosis of PML was based on the microscopic appearance of the biopsies and immunostaining for SV-40-related antigen. In one of these patients the diagnosis was also supported by PCR for the JC virus. In two patients whose biopsies were only suggestive of PML, a definitive diagnosis was possible utilizing immunohistochemistry and PCR. In another case the histopathologic features were atypical of PML, and the diagnosis was established with immunostaining and PCR. The diagnosis of PML was established by PCR alone in two patients whose biopsies showed only suggestive or nonspecific findings. We conclude that the accuracy of stereotactic biopsy in the diagnosis of PML is enhanced by using a combination of light microscopy, immunohistochemistry and PCR.

Canine ehrlichiosis in Egypt: sero-epidemiological survey.

A total of 374 dogs, 252 from five military kennels and 122 privately owned, were tested for Ehrlichia canis antibody. Sera were tested at a 1:20 dilution by indirect fluorescent antibody with the use of E. canis cell-culture antigen slides. The overall prevalence of E. canis antibody was 33%. Antibody prevalence among military dogs (29%) was significantly lower than among privately owned dogs (41%; P < 0.05). The E. canis seroprevalence among dogs infested with ticks (Rhipicephalus sanguineus) was higher (44%) than that among uninfested dogs (31%; P = 0.08). The seroprevalence among military dogs varied from 21-46% at the five kennels; lower prevalences were observed in kennels with higher sanitary and hygienic conditions. Age- and sex-related E. canis antibody prevalences were not significantly different among military and privately owned dogs, although adult and male privately owned dogs had the highest seroprevalences (45% and 44%, respectively). Three dogs with epistaxis had E. canis antibody titres > 1:320. These data demonstrate the first laboratory evidence of E. canis infection among dogs in Egypt.

An overview of internet biosurveillance.

Internet biosurveillance utilizes unstructured data from diverse web-based sources to provide early warning and situational awareness of public health threats. The scope of source coverage ranges from local media in the vernacular to international media in widely read languages. Internet biosurveillance is a timely modality that is available to government and public health officials, healthcare workers, and the public and private sector, serving as a real-time complementary approach to traditional indicator-based public health disease surveillance methods. Internet biosurveillance also supports the broader activity of epidemic intelligence. This overview covers the current state of the field of Internet biosurveillance, and provides a perspective on the future of the field.