Experimental evidence against replication or dissemination of hepatitis C virus in mosquitoes (Diptera:Culicidae) using detection by reverse transcriptase polymerase chain reaction.

In 3 laboratory experiments, mosquitoes were fed hepatitis C virus (HCV)-RNA positive blood by using membrane feeders, separated into head, thorax, and abdomen, and tested by a reverse transcriptase polymerase chain reaction for HCV-RNA. HCV did not replicate or disseminate in mosquitoes that had ingested blood from patients that were HCV-viremic positive. When yellow fever mosquitoes, Aedes aegypti (L.), were held for 1, 3, 7, 14, and 21 d after feeding, HCV-RNA was detected in the abdomens of 5/5 mosquitoes at 1 d after feeding; remaining tissues were negative with the exception of a single positive head at 7 d. In agreement, HCV-RNA was detected in Asian tiger mosquito, Aedes albopictus Skuse, and Anopheles stephensi Liston abdomens at 1 d, but not 3 d after feeding no HCV-RNA was detected in heads or thoraces. In addition, HCV-RNA was detected in heads of Ae. aegypti at 10 and 20 min, but not at 30 min, after feeding. The latter results raise the possibility of HCV contamination of mouthparts and, theoretically, mechanical transmission of this virus.

Cryptogenic liver disease in the United States: further evidence for non-A, non-B, and non-C hepatitis.

UNLABELLED: Since the advent of anti-hepatitis C virus (HCV)-testing, the current worldwide prevalence of cryptogenic cirrhosis is essentially unknown. OBJECTIVES: 1) determine if serum HCV RNA testing by the polymerase chain reaction (PCR) enhances the diagnostic yield for HCV in patients with anti-HCV-negative cryptogenic liver disease and 2) further define the epidemiology of patients with indeterminate causes of chronic hepatitis and cirrhosis. METHODS: We reviewed the records of 567 patients with chronic liver disease who were evaluated over a 3-yr period. A definite etiology for liver disease was established in all but 28 patients (4.9%). Histology was available in 20 patients. RESULTS: Twenty-one of the 28 patients were female (mean age, 52 yr). Thirteen patients (46%) had a history of previous blood transfusion, and one patient was a health care worker. Histology revealed CAH/cirrhosis in 17 patients, CPH in one patient, and no diagnosis in two patients. Five additional patients had clinically advanced cirrhosis. None of the 28 patients with cryptogenic chronic liver disease was HCV RNA positive by PCR. CONCLUSIONS: 1) Approximately 5% of patients with chronic hepatitis/cirrhosis remain cryptogenic despite the addition of HCV RNA testing. 2) PCR does not improve the diagnostic yield in this population. 3) Nearly half of the patients with presumed cryptogenic cirrhosis have been transfused, supporting the hypothesis of a non-A, non-B, and non-C hepatitis virus. 4) Screening donor blood for serum ALT may still be necessary to further reduce posttransfusion hepatitis.

HCV RNA is present in the menstrual blood of women with chronic hepatitis C infection.

OBJECTIVES: To further determine potential routes of sexual transmission of hepatitis C virus (HCV), we examined the menstrual blood of women chronically infected with this virus. METHODS: Ten premenopausal women with documented HCV infection were studied. All patients were anti-HCV positive by ELISA-II and positive for HCV RNA by polymerase chain reaction. Eight patients acquired their infection via intravenous drug abuse, one patient through blood transfusion, and one patient was a health care worker. Liver biopsies showed evidence of chronic hepatitis in all patients. Menstrual blood was collected on the first day of menses utilizing a sterile 15-ml conical centrifuge tube. Total RNA was isolated from serum by the one-step guanidinium method. Reverse transcriptase polymerase chain reaction was performed with "nested" primers from the 5' noncoding region of the HCV genome. All samples were run twice, and negative controls were run with each sample. Three anti-HCV negative volunteers served as controls. RESULTS: HCV RNA was present in the menstrual blood of all chronically infected patients tested. All controls were negative for menstrual blood HCV RNA. CONCLUSIONS: 1) HCV RNA is routinely present in the menstrual blood of women chronically infected with this virus. 2) Knowledge of the presence of HCV RNA in menstrual blood should help facilitate appropriate guidelines for the sexual counseling of patients with chronic HCV infection.