ABSTRACT
Objective: To establish a surveillance in Dong Thap, at the border with Cambodia by assessing the presence of DENV serotypes and CHIKV among patients hospitalized at Dong Thap general hospital. Methods: Cross-sectional descriptive analysis was conducted on a cohort of 131 patients hospitalized with acute fever and symptoms compatible with dengue or chikungunya. The study was conducted from January 2012 to February 2013. The full clinical picture was established as well as serological and molecular detection. Serological analysis was sequentially performed on blood samples collected on admission and an average of seven days after admission. The detection of IgM antibody to DENV was performed by IgM capture ELISA and the detection of DENV and CHIKV RNA was done by reverse-transcription multiplex PCR. Results: 101 patients out of 131 (77%) were confirmed with dengue. All four dengue serotypes were detected with a predominance of DENV2 and DENV4. No chikungunya infection was detected although reported in neighboring Cambodia. A differential efficiency of serological dengue detection was observed. Efficiency was 29% upon admission and 53% after seven days on the same patients. 30 patients out of 131 (23%) were negative with both DENV and CHIKV. Conclusions: Dengue is at risk of being underestimated and chikungunya is not systematically detected. Changes in detection and surveillance procedures are therefore discussed to increase efficiency of dengue detection and continue the monitoring the emergence of CHIKV in Dong Thap province and in Vietnam.
ABSTRACT
OBJECTIVE@#To establish a surveillance in Dong Thap, at the border with Cambodia by assessing the presence of DENV serotypes and CHIKV among patients hospitalized at Dong Thap general hospital.@*METHODS@#Cross-sectional descriptive analysis was conducted on a cohort of 131 patients hospitalized with acute fever and symptoms compatible with dengue or chikungunya. The study was conducted from January 2012 to February 2013. The full clinical picture was established as well as serological and molecular detection. Serological analysis was sequentially performed on blood samples collected on admission and an average of seven days after admission. The detection of IgM antibody to DENV was performed by IgM capture ELISA and the detection of DENV and CHIKV RNA was done by reverse-transcription multiplex PCR.@*RESULTS@#101 patients out of 131 (77%) were confirmed with dengue. All four dengue serotypes were detected with a predominance of DENV2 and DENV4. No chikungunya infection was detected although reported in neighboring Cambodia. A differential efficiency of serological dengue detection was observed. Efficiency was 29% upon admission and 53% after seven days on the same patients. 30 patients out of 131 (23%) were negative with both DENV and CHIKV.@*CONCLUSIONS@#Dengue is at risk of being underestimated and chikungunya is not systematically detected. Changes in detection and surveillance procedures are therefore discussed to increase efficiency of dengue detection and continue the monitoring the emergence of CHIKV in Dong Thap province and in Vietnam.
ABSTRACT
Objective: To record the human cases of dengue fever (DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics. Methods: 24 different outbreak points were recorded in 8 districts between August and December 2011. Results: 140 patients were hospitalized following dengue diagnostic with a predominance of males (59.3%) and the 15-34 age class. Only DENV-1 (11.27%) and DENV-2 (88.73%) serotypes were detected in human samples. Mosquito sampling performed in and around patients households revealed the predominance of Aedes aegypti (A. aegypti) (95.15%) versus Aedes albopictus (4.85%). Conclusions: There is a positive correlation between the population density of A. aegypti and the number of human cases and duration of outbreaks. This was not observed for Aedes albopictus. Three pools of A. aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.
ABSTRACT
OBJECTIVE@#To record the human cases of dengue fever (DF) and investigate the Aedes mosquito species circulating during the Hanoi 2011 DF epidemics.@*METHODS@#24 different outbreak points were recorded in 8 districts between August and December 2011.@*RESULTS@#140 patients were hospitalized following dengue diagnostic with a predominance of males (59.3%) and the 15-34 age class. Only DENV-1 (11.27%) and DENV-2 (88.73%) serotypes were detected in human samples. Mosquito sampling performed in and around patients households revealed the predominance of Aedes aegypti (A. aegypti) (95.15%) versus Aedes albopictus (4.85%).@*CONCLUSIONS@#There is a positive correlation between the population density of A. aegypti and the number of human cases and duration of outbreaks. This was not observed for Aedes albopictus. Three pools of A. aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.
ABSTRACT
From 2000ml supernatant fluid of infected Aedes albopictus cells clone C6/36, Nam Dinh virus antigen was prepared by ultracentrifuge generating 5ml purified antigen. Protein content of the purified antigen is 4.4 mg/ml and antigen titer stabilizes for two years at - 80oC. The purified antigen was used for detecting IgM against Nam Dinh virus in cerebrospinal fluid from acute encephalitis syndrome patients by indirect IgM-ELISA. The examination of 814 cerebrospinal fluid samples of acute encephalitis syndrome, which were confirmed non-Japanese encephalitis during 1998 - 2004. The positive proportion with Nam Dinh virus antigen has been found to be 6.59 % - 20.06%. Most of positive cases in children were under 15 years old. Acute encephalitis syndrome cases due to Nam Dinh virus mainly occurred in May, June and July, in the same season of Japanese encephalitis in the Northern area of Vietnam.
Subject(s)
Antigens , Encephalitis , Viruses , DiagnosisABSTRACT
During 2003 - 2004, in total 976 sera and cerebrospinal fluid samples from patients with acute encephalitis syndrome (AES) were collected from Pediatric Hospital, several Centers of Preventive Medicine and National Institute of Hygiene and Epidemiology, Tay Nguyen for screening viral pathogens cause AES using MAC-ELISA with Japanese encephalitis (JE), West Nile and Nam Dinh virus antigens. Results: Out of 976 sera and cerebrospinal fluid samples of AES patients were screened using JE virus antigen, 46.1% (454/976) cases were confirmed to be JE virus infection. Out of 239 cerebrospinal fluid samples of AES patients were screened by Nam Dinh virus antigen, 13.4% (32/239) cases were confirmed to be Nam Dinh virus infection. Out of 103 sera and cerebrospinal fluid samples of AES patients were screened by West Nile virus antigen, there were no positive result was confirmed with this antigen. To date, JE virus is leading cause of AES in Vietnam, with over 80% cases in children under 15 years old. It should be intensive JE vaccination for all children under 15 years old in order to control JE soon.
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In 2004, 13 mosquito samples and 31 pig blood samples were collected at reveral districts, Gia Lai province for virus isolating. Isolating virus was carried out by Aedes albopictus clone C6/36 cells. Identifying virus was implemented by RT-PCR with generate primers of Alpha, Bunya, Flavi viruses and specific primers of Japanese encephalitis and Nam dinh virus. Result: one Japanese encephalitis virus strain was isolated from pig blood samples at Ia Grai, Gialai and six Nam dinh virus strains were isolated from Clux tritaeniorhynchus, Culex vishnui and Culex gelidus at Chu se, Gia Lai.
Subject(s)
Encephalitis, Japanese , VirusesABSTRACT
Haemagglutination Inhibition Technique was applied to study conversion anti-Japanese encephalitis (JE) virus antibodies in pigs in Hoai Duc, Ha Tay, in 2002. The results showed that antibody conversion in pigs occurs year-round. Vero and C6/36 cells were used to isolate JE virus. From 83 mosquito pools and 30 pig blood samples, 7 JE viruses strains were isolated from mosquito pools, and 4 JE viruses strains were isolated from pig blood samples. These JE viruses strains were isolated either in the epidemic or in the non epidemic season. Sequencing of E gene region of JE virus strains that were isolated from mosquitoes and pigs, circulating of genotype I of JE virus in North Vietnam in 2002
Subject(s)
Encephalitis Virus, Japanese , Encephalitis Viruses , Encephalitis , VirusesABSTRACT
In the year 2002, a new arbovirus strain coded 02VN208 was isolated from cerebro- spinal fluid of patients with acute encephalitis syndrom by C6/36 mosquito cell lines. It’s a virus of 50nm spherical enveloped shape with ARN genetic materia. From a part of the extended sequence,specific primer pair was designed for determining the virus strains of the patients and the mosquitoes isolated by RT-PCR . 6 viral strains belonging to the same genotype of 02VN208 viral strain were confirmed. Results suggested that it’s a new arbovirus named Namdinh virus. Further study should be developed serologically and ultra morphologically
Subject(s)
Encephalitis , Viruses , Diagnosis , Cerebrospinal Fluid , EpidemiologyABSTRACT
The analysis of evolutionary of JE virus in the North Vietnam was examined through 1,000 nucleotides of the envelope gene region encoded the E protein. 9 JE virus strains isolated from Vietnamese patients were sequenced and compared with previous published JE virus strains. The results showed that the Vietnamese strains isolated from human brain between 1986 and 1989 clustered in genotype 3. The strains isolated from mosquitoes and pigs between 2001 and 2002 clustered in genotype 1. The emerging JE virus genotype 1 in the North Vietnam among isolates from mosquitoes and pigs in the last few years was recorded for the first time. But JE virus genotype 1 was not detected among isolates from Vietnamese JE patients so far
Subject(s)
Encephalitis, Japanese , Epidemiology , VirusesABSTRACT
453 cases of acute encephalitis syndrome were studied in the year 2002 at the National Institute of Pediatrics and 21 provinces of North Vietnam. Using Aedes albopictus clone C6/36, from CSF, 6 strains of Japanese encephalitis virus were isolated. By ELISA – Sandwich technique and indirect immunofluorescent assay, 4 virus strains were determined, including 4 strains of JE virus and 2 unknown viruses. 43.26% of cases of acute encephalitis syndrome were caused by JE virus. JE incidence in children of 1-4 years old reduced from 37.62% in 1989-1995 year period to 11.22% in 2002, due to the intensive immunization for children 1-5 years old.
Subject(s)
Encephalitis, Japanese , Encephalitis , Disease , EpidemiologyABSTRACT
In September – December 2001 period, from 4987 female Culex mosquitoes collected in Cat Que commune, Hoai Duc district, Ha Tay province, 4 viral species were isolated by clone C6/36 cells of Vero and Aedes albopictus. Among them, 2 species were alpha virus, 01VN61 virus was isolated from Culex tritaeniorhynchus and 01VN62 virus from Culex gelidus, both strains were adapted to 1-2 days age mice. By sequencing technique on E1 gene and 3 NCR gene area, 01VN62 virus was identified as Safiyama virus, a virus of alpha virus
Subject(s)
Alphavirus , Culicidae , CulexABSTRACT
From 2001 September to 2002 August, 566 serum samples of 5-6 months pig at Hoai Duc district, Ha Tay province were supervised. Results showed very high frequency of JE infection among pig population during epidemic season with the percentage of positivity was 82% in June. By contrast during another months of non-epidemic season, the frequency of JE infection among pig population was very low, with the percentage of positivity was between 1.96% and 14%