SEARCH · PubMed Health

Results for “outbreak response”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources

PubMed1998

Genomic and antigenic variations of porcine reproductive and respiratory syndrome virus major envelope GP5 glycoprotein.

The objective of the present study was to evaluate the importance of genomic and antigenic variations which may have affected the major envelope glycoprotein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) isolates responsible for outbreaks in Quebec and Ontario, in comparison with the modified-live U.S. vaccine strain (MLV) and the European prototype strain from Lelystad (LV). Nucleotide sequence analyses of the open reading frame (ORF)5 genes showed that all of the isolates studied were heterogenous, amino acid (aa) identities varied from 88 to 99% with the MLV strain, and between 51 and 54% with the LV strain. The aa substitutions were randomly scattered across the protein, although one region between residues 26 and 39 was found to correspond to a hypervariable region which involved 0 to 3 potential N-glycosylation sites. The ORF5 encoded products of 5 of these isolates, including the MLV and LV strains, were expressed in E. coli as recombinant proteins fused to the glutathione S-transferase (GST) protein and used to raise hyperimmune anti-ORF5 sera in rabbits. The reactivity patterns of strain-specific hyperimmune anti-ORF5 sera and a panel of 4 monoclonal antibodies directed against the ORF5 gene product of the Quebec IAF-Klop strain of PRRSV, indicated that GP5 of field isolates also underwent antigenic variations. The data suggest that neutralizing epitopes, independent of conformation and glycosylation, are also associated with antigenic variability of the GP5 of PRRSV.

Amino Acid Sequence↗

PubMed1998

Viability of Cryptosporidium parvum oocysts in natural waters.

Water-borne transmission of the coccidium Cryptosporidium parvum Tyzzer, 1912 is frequently responsible for outbreaks of human cryptosporidiosis. One of the most important was reported in 1993 in Milwaukee in the United States, where 403,000 cases were recorded. The determination of the percentage of oocysts excystated is the first step in evaluating their viability, but it alone is not sufficient. This percentage depended on the conditions of storage and also the presence of oxidant or disinfectent agents in water. The percentage of excystation is not always related to viability. Therefore, determination of the viability of excysted sporozoites by determining their infectivity for enterocytic Caco2 cell lines in culture provides information essential for evaluating the risk of contaminated drinking water.

Animals↗

PubMed1976

The value of complement fixation and haemagglutination inhibition tests in the diagnosis of influenza A.

Antibody response of 133 influenza A patients from three outbreaks since 1972-73 was analyzed by complement fixation (CF) and haemagglutination inhibition (HI) methods. During the first outbreak, a significant response was more often measured by CF than by HI. During the last outbreak HI appeared more useful than CF for routine serological diagnosis; 23% of cases verified by HI were missed by CF. The poor response of CF antibodies was associated with the high level of pre-infection antibodies.

Adolescent↗

PubMed1990

The immune response in a cat-related outbreak of Q fever as measured by the indirect immunofluorescence test and the enzyme-linked immunosorbent assay.

The isotypic immune response of 16 individuals who developed Q fever pneumonia following exposure to an infected parturient cat was studied. The enzyme-linked immunosorbent (ELISA) test was used to detect IgM, IgA, and IgG antibodies to phase I and phase II Coxiella burnetii whole-cell antigens and to the phase I lipopolysaccharide. The indirect immunofluorescent antibody (IFA) test was also used to detect antibodies to phase I and phase II whole cells. None of the 16 subjects developed antibodies to the phase I lipopolysaccharide. The ELISA was more sensitive than the IFA test. IgM antibodies to phase II antigen were detectable by ELISA in 80% of the subjects at the time of onset of symptoms and were still present in 7 of the 8 tested at 32 weeks following the onset of symptoms. In all instances (ELISA: IgG, IgM; IFA: IgG, IgM) phase II antibodies developed earlier and reached higher levels than did phase I antibodies. The absence of antibodies to phase I lipopolysaccharide in acute Q fever combined with our unpublished findings of antibodies to phase I lipopolysaccharide in chronic Q fever suggests that this test may be used to distinguish acute from chronic Q fever.

Adult↗

PubMed1998

New perspectives on the role of Escherichia coli O157:H7 and other enterohaemorrhagic E. coli serotypes in human disease.

This review compares the rates of detection of non-O157:H7 enterohaemorrhagic Escherichia coli (EHEC) with EHEC O157:H7 in outbreaks and sporadic cases of human disease by analysing Australian data and the world literature. Numerous outbreaks of disease have been attributed to EHEC O157:H7. In many studies, isolation rates of this organism have been low and attempts to seek other EHEC have not been made. Ease of isolation and identification of the O157:H7 serotype may have given the impression that this serotype was the sole organism responsible for the outbreaks. Careful review and analysis shows that serotypes other than O157:H7 also play an important role in human disease. Evidence is presented from several overseas outbreaks described in the literature, as well as from investigations of the Adelaide O111:H- outbreak, that suggests an association between severity of disease and multiple infecting serotypes. While not diminishing the role of the O157:H7/H- clone, this review indicates that other serotypes can be responsible for outbreaks as well as cases of sporadic human disease. The current focus on O157:H7 has major implications in terms of diagnosis, the food industry and human health.

Australia↗

PubMed1996

Evaluation of the use of mass chemoprophylaxis during a school outbreak of enzyme type 5 serogroup B meningococcal disease.

BACKGROUND: A vaccine for prevention of serogroup B meningococcal disease is not available in the United States, and indications for the use of mass chemoprophylaxis for control of meningococcal outbreaks are not well-defined. In response to an outbreak of six cases of enzyme type 5 serogroup B meningococcal disease among students at a middle school, we implemented a program of mass rifampin prophylaxis and evaluated the effectiveness of this preventive measure. METHODS: Oropharyngeal cultures were obtained from 351 of the 900 students before prophylaxis; 196 participants were recultured 3 weeks later. Meningococcal isolates were subtyped and tested for rifampin susceptibility, and risk factors for disease or carriage among students were evaluated. RESULTS: No cases occurred after prophylaxis. Before prophylaxis 10% (34 of 351) of students were meningococcal carriers and 3.4% (12 of 351) carried the epidemic strain. After prophylaxis 2.5% (5 of 196) were carriers and 1.0% (2 of 196) carried the epidemic strain. Rifampin was 85% effective in eradicating carriage, and the rate of acquisition of carriage during the 3-week period was low (0.5%). Carriage persisted after prophylaxis in 4 students; 3 of these postprophylaxis isolates were rifampin-resistant. Rifampin resistance thus developed in 12% (3 of 26) of preprophylaxis isolates. Disease/epidemic strain carriage was associated with enrollment in the school band and certain other classes. CONCLUSIONS: These findings suggests that mass chemoprophylaxis may be effective and should be considered for control of school serogroup B meningococcal outbreaks. This approach is less likely to be effective for control of outbreaks affecting larger, less well-defined populations and is associated with the rapid development of antibiotic resistance.

Adolescent↗

PubMed1978

Neonatal infections in puppies caused by Escherichia coli serogroups 04 and 025.

Three cases of neonatal E. coli infection in Newfoundland dogs are described. The serological examination showed that the implicated E. coli belonged to sero-group 04 in two outbreaks while sero-group 025 was responsible for one outbreak. In one of the kennels with implication of 04, this 0-group was also isolated from adult dogs with diarrheal conditions.

Animals↗

PubMed1990

Outbreak of nosocomial infections due to Klebsiella pneumoniae producing SHV-4 beta-lactamase.

One hundred and fifty-four clinical isolates of Klebsiella pneumoniae resistant to broad-spectrum cephalosporins, aztreonam and amikacin were responsible for an outbreak of nosocomial infections lasting eight months in a university hospital in Paris. This outbreak occurred in the intensive care unit (39 patients), haematology units (8 patients) and surgical and medical units (11 patients). Antibiotic resistant strains were isolated from the urinary tract (48%), wound and drainage fluids (21%), respiratory tract (14%), blood (12%) and stools (5%). High resistance to oxyimino-beta-lactams was mediated by a plasmid-encoded beta-lactamase with an isoelectric point of 7.8 (SHV-4). This CAZ-type enzyme conferred a higher level of resistance to ceftazidime and aztreonam (geometric mean MIC 135 mg/l) than to cefotaxime (geometric mean MIC 14 mg/l). All isolates were of the same biotype (weakly urease positive and no sucrose fermentation). Eight Klebsiella pneumoniae strains isolated in different units and at different times of the outbreak were of the same serotype, had common plasmid patterns and harboured a large self-transferable plasmid of about 180 kilobases encoding resistance to penicillins, oxyimino-beta-lactams, aminoglycosides, tetracycline and trimethoprim. These eight large plasmids had indistinguishable EcoRI restriction patterns. These results suggest that a single strain of Klebsiella pneumoniae was responsible for this outbreak.

Anti-Bacterial Agents↗

PubMed1997

Preliminary observations on factors responsible for long persistence and continued outbreaks of plague in Lushoto district, Tanzania.

Human plague has been an important public health problem in Tanzania for over a century. Recorded outbreaks of the disease have been reported from various parts of Tanzania, including Iringa, Kagera, Singida, Mbulu, Arusha and Kilimanjaro since 1886. Since 1980 however, only Lushoto, Singida and Karatu districts have experienced outbreaks of the disease. Of these areas, Lushoto has disproportionately high incidences of the disease and this has persisted for nearly 17 years. Efforts to curb the disease through conventional methods, including control of vectors and reservoirs, chemotherapy and chemoprophylaxis, enforcement of sanitation improvement as well as health education, have been applied every year, but plague cases and deaths continue to occur in the area to date. During the period April 1980 to December 1996, a total of 6599 cases with 580 (8.8%) deaths were recorded. Biological factors, such as the presence of suitable rodent reservoirs, efficient flea vectors and plague bacillus, could be partly responsible for the long persistence and recurrence of the disease. Since such factors are also common in other plague foci where the disease has never been persistently recurrent, and where indigenous people are culturally different from those in Lushoto, it is assumed that socio-cultural factors play an important role as determinants of the disease in the latter district. This paper reports preliminary observations on socio-cultural, biological and environmental factors which are thought to be, at least partly, responsible for the long persistence and repeated outbreaks of plague in the district. These include traditional beliefs on the cause and health seeking behaviour for treatment of plague, sleeping and food storage habits, large populations of rodents and fleas, and status of the immediate environment.

Adult↗

PubMed1980

Application of serological typing to the investigation of outbreaks of Clostridium perfringens food poisoning, 1970-1978.

Serological typing was used as an epidemiological tool in the investigation of 524 outbreaks of Clostridium perfringens food poisoning in the United Kingdom and 37 outbreaks in other countries. Five thousand five hundred and fifty-four (77%) of 7245 strains of C. perfringens associated with the 561 outbreaks were typable with the 75 Food Hygiene Laboratory antisera; in 354 (63%) of these outbreaks a specific serotype was established as being responsible for the outbreak. An assessment is made of the ability of two additional sets of antisera, prepared against 34 American and 34 Japanese strains of C. perfringens, to increase the number of strains which can be typed. The extent of cross-reaction between the three sets of antisera was determined and the results are discussed in relation to the source and history of the type strains.

Clostridium Infections↗

PubMed1992

Association of hepatitis E virus with an outbreak of hepatitis in Pakistan: serologic responses and pattern of virus excretion.

Hepatitis E virus (HEV), a positive-strand RNA agent, has been associated with enterically transmitted non-A, non-B hepatitis in Asia, Africa, and Mexico. To evaluate the role of HEV in an outbreak of hepatitis in Pakistan, we used immune electron microscopy to detect 1) antibody to HEV, for evidence of infection, and 2) virus, to determine the pattern of HEV excretion. Paired sera from 2 patients were assayed for antibody by using reference HEV: one seroconverted, an atypical finding for HEV infections; the other had high levels of anti-HEV in both sera. Virus particles with the size (29 x 31 nm) and morphology of HEV were detected in feces from 10 of 85 patients and serologically identified as HEV by using reference antibodies from an HEV-infected chimpanzee. One of these HEV-containing specimens was collected 9 days before the onset of jaundice; it was among feces from 38 outpatients with nonspecific symptoms and biochemical hepatitis, 12 of whom subsequently developed jaundice. The other 9 feces with HEV were among 36 collected within 7 days of the onset of acute icteric hepatitis; all 11 feces from days 8 to 15 were negative for HEV. Fecal concentrations of HEV appeared to be lower than those of many enteric viruses: only one specimen contained as many as 5 particles per EM grid square. It is concluded that HEV was etiologically associated with the epidemic and was predominantly excreted at very low levels during the first week of jaundice.

Antibodies, Viral↗

PubMed1997

Pulsed-field gel electrophoresis analysis of clonal relationships among Neisseria meningitidis A strains from different outbreaks.

Pulsed-field gel electrophoresis was used to analyze the DNA of 67 Neisseria meningitidis A strains from five African outbreaks occurring between 1988 and 1996. Endonuclease Bg/II was used to cut chromosomal DNA, generating 19 analyzable fragments. This technique allowed comparison of clonal relationships between outbreak strains and revealed that the same pulsotype was responsible for the outbreaks. This pulsotype is closely related to strain B54, subgroup III reference strain, Finland, 1975, showing only two fragment differences.

Africa↗

PubMed1997

An outbreak of invasive group A streptococcal disease associated with high carriage rates of the invasive clone among school-aged children.

OBJECTIVES: To determine if a common strain of group A streptococcus was responsible for an outbreak of invasive streptococcal disease in southeastern Minnesota and to determine whether this strain was prevalent among residents of this area during the outbreak who either had streptococcal pharyngitis or were asymptomatic streptococcal carriers. DESIGN: Pharyngeal culture survey and case-contact evaluation. SETTING: Three adjacent counties in southeastern Minnesota defined as the outbreak area. Outbreak period, January 1 through March 31, 1995. PATIENTS: Seven patients with invasive streptococcal infection, 1249 patients (adults and children) with sore throat who resided in the outbreak area, children from an elementary school located in 1 community where the majority of invasive cases occurred, and 896 students from 3 schools located in Minnesota counties outside the outbreak area. MEASUREMENTS: Pulsed-field gel electrophoresis (DNA fingerprinting) of group A streptococcal isolates obtained from patients with invasive disease, throat swabs of patients with sore throat, and throat swabs of asymptomatic school-aged children. RESULTS: All patients with outbreak-associated invasive disease had group A streptococcal isolates that were indistinguishable by pulsed-field gel electrophoresis. Additional testing showed that these isolates carried significant virulence factors including pyrogenic exotoxin A and streptococcal superantigen. Five of these 7 patients with invasive disease had underlying medical conditions; 4 developed toxic shock syndrome and died (case fatality, 57%). The outbreak-associated group A streptococcal clone was found in 69 (26.5%) of the 260 patients with sore throat from whom group A streptococcus was isolated. The frequency of the outbreak clone among pharyngeal carriers from the 3 schools outside the outbreak area was significantly less (range, 0%-10%) than in children from the school in the outbreak area (78%; relative risk, 29; 95% confidence interval, 11.1-78.1; P<.001). Four of the 7 patients with outbreak-associated disease had contact with children who attended the school in the outbreak area. CONCLUSIONS: A single clone of group A streptococcus was responsible for 7 cases of invasive streptococcal disease during an outbreak in Minnesota and for a significant number of pharyngitis cases that also occurred during the outbreak. Invasive disease occurred most frequently in persons with underlying medical conditions. This outbreak was also associated with increased carriage rates of the invasive streptococcal clone among community school-aged children. Cases of invasive group A streptococcal infection may therefore reflect the tip of the iceberg with regard to the burden of colonization of a specific invasive streptococcal clone in a community.

Adult↗

PubMed1998

Outbreaks of waterborne infectious intestinal disease in England and Wales, 1992-5.

Following the introduction of an improved surveillance system for infectious intestinal disease outbreaks in England and Wales, the Public Health Laboratory Service Communicable Disease Surveillance Centre received reports of 26 outbreaks between 1 January 1992 and 31 December 1995 in which there was evidence for waterborne transmission of infection. In these 26 outbreaks, 1756 laboratory confirmed cases were identified of whom 69 (4%) were admitted to hospital. In 19 outbreaks, illness was associated with the consumption of drinking water from public supplies (10 outbreaks) or private supplies (9 outbreaks). The largest outbreak consisted of 575 cases. In 4 of the remaining 7 outbreaks, illness was associated with exposure to swimming pool water. Cryptosporidium was identified as the probable causative organism in all 14 outbreaks associated with public water supplies and swimming pools. Campylobacter was responsible for most outbreaks associated with private water supplies. This review confirms a continuing risk of cryptosporidiosis from chlorinated water supplies in England and Wales, and reinforces governmental advice to water utilities that water treatment processes should be rigorously applied to ensure effective particle removal. High standards of surveillance are important for prompt recognition of outbreaks and institution of control measures. As microbiological evidence of water contamination may be absent or insufficient to implicate a particular water supply, a high standard of epidemiological investigation is recommended in all outbreaks of suspected waterborne disease.

Communicable Diseases↗

PubMed1995

An outbreak of occupational dermatosis in an electronics store.

An outbreak of skin disorders was noted by the primary care physician responsible for the health care of 52 employees in an electronics store. The cases occurred after termite treatment of the store, and the breakdown of the air-conditioning system in several areas in the store. Investigations were initiated to allay worker concern that the chemicals used for termite treatment (in particular, arsenic trioxide) were responsible for the outbreak. 9 of the 52 workers were found to have heat rash (miliaria rubra). 21% (7) of workers who worked in non-air-conditioned areas had heat rashes, as compared to 11% (2) of workers who worked in air-conditioned work zones. 2 workers had contact dermatitis due to exposure to greaseless lubricant, and 8 other workers had a non-work-related skin disorder. Indoor wet bulb globe temperature index measurements in the non-air conditioned areas were within threshold limit values, but ventilation in these areas was very poor. 2 environmental samples had non-detectable limits of arsenic.

Air Conditioning↗

PubMed1990

An outbreak of human Semliki Forest virus infections in Central African Republic.

Semliki Forest (SF) virus was responsible for an outbreak of febrile illnesses in Bangui, Central African Republic (CAR), during October-December 1987. The virus was isolated at first from mosquitoes, mainly Aedes africanus, collected August-October in a gallery forest 100 km from Bangui. During October-December, 22 isolations of SF virus were made from serum samples collected from patients in Bangui presenting with fever, severe persistent headache, myalgia, arthralgia, and a convalescence marked by asthenia. During the same period, 8 SF virus isolates were obtained from mosquitoes collected in Bangui, mainly from Ae. aegypti. Europeans, particularly soldiers who had recently arrived from France, were affected. Antibodies to alphaviruses had been previously detected in a high proportion of resident human populations in CAR. We conclude that SF virus is a human pathogen.

Aedes↗

PubMed1995

Emergence of nalidixic acid resistant Shigella dysenteriae type 1 in Thailand: an outbreak associated with consumption of a coconut milk dessert.

BACKGROUND: Although Shigella dysenteriae type 1 has been responsible for large outbreaks of severe dysentery in many parts of Asia, relatively few cases of this disease have been reported from Thailand and have generally not involved nalidixic acid resistant strains. METHODS: Beginning March 1991, all patients with diarrhoea seen at the hospital outpatient department (OPD) in Suan Phung, Thailand (a western district near the Burmese border) were cultured for enteric pathogens. Shigella dysenteriae 1 was first recognized in July 1992, and an OPD-based case-control study was conducted to pinpoint the source of the outbreak in the community. For each case of culture confirmed S. dysenteriae 1, one control person without diarrhoea, matched by age and date of visit, was randomly selected from the OPD registry. RESULTS: Of 197 patients treated for diarrhoea at the hospital OPD in July and August 1992, 79 (40%) had bloody diarrhoea, compared with 86/561 (15%) patients seen during 16 months of previous surveillance (P < 0.0001). Shigella dysenteriae 1 was isolated from 33/197 (17%) patients. Compared to matched controls, patients with S. dysenteriae 1 were more likely to attend one of the local elementary schools (odds ratio = 6.74, P = 0.025), or live in the community surrounding this school (odds ratio for non-school age people = 18.0, P = 0.008). A cross-sectional study conducted at the school indicated that 50 (10%) of 485 students had dysentery in July. A coconut milk dessert prepared at the school was identified as the vehicle of transmission (relative risk = 24.9, P < 0.0001). CONCLUSIONS: Nalidixic acid resistant S. dysenteriae 1 emerged in a community in Thailand, and was traced to a point source outbreak at a local school.

Adolescent↗

PubMed1979

Evaluation of a neuraminidase-specific influenza A virus vaccine in children: antibody responses and effects on two successive outbreaks of natural infection.

Three groups of children were immunized with an inactivated Port Chalmers (H3ChN2Ch) influenza vaccine (group A), a neuraminidase-specific (Heq1N2Ch) influenza vaccine (group B), or a placebo. Immunization induced seroconversion for H3Ch and N2Ch-specific antibody in group A and for N2Ch antibody in group B. The protective efficacies observed against naturally acquired illness with the Port Chalmers strain of influneza A virus were 68.7% and 37.4% in groups A and B, respectively, in comparison to the placebo group, and those against illness produced by the subsequent outbreak of the Victoria strain were 80.0% and 72.7%. These data support the role of neuraminidase-specific immunization in protection against influenza. Although the degree of protection after vaccination with the Heq1N2Ch vaccine was less than that provided by the biphasic H3ChN2Ch vaccine against the Port Chalmers strain, it appeared to be similar in the two vaccine study groups against the Victoria strain.

Adolescent↗