In vitro evaluation of the composition and acaricidal efficacy of Urtica fissa leaf ethyl acetate extract against Sarcoptes scabiei mites.

In veterinary medicine, natural products provide an alternative to chemical agents for mite management. In the present study, the acaricidal efficacy of Urtica fissa leaf ethyl acetate extract against Sarcoptes scabiei mites was examined. The chemical composition of the extract was determined using liquid chromatography-mass spectrometry (LC-MS) analysis. The ethyl acetate extract was found to be extremely toxic to mites at a concentration of 100 mg/ml (m/v), killing all S. scabiei within two hours. The median lethal time (LT50) values for ethyl acetate extract concentrations of 25, 50, and 100 mg/ml against S. scabiei were 1.706, 1.204, and 0.750 h, respectively. The median lethal dosage (LC50) for S. scabiei was 19.14 mg/ml at two hours. The chemical composition of the ethyl acetate extract was evaluated using LC-MS, showing that the major components were schaftoside (8.259%), carnosol (6.736%), prostaglandin A2 (5.94%), 13(S)-HpOTrE (4.624%), nandrolone (4.264%), 1H-indole-3-carboxaldehyde (4.138%), 9-oxoODE (3.206%), and stearidonic acid (2.891%). In conclusion, these findings indicate that Urtica fissa contains promising new acaricidal compounds capable of successfully controlling animal mites.

Natural Products as Mite Control Agents in Animals: A Review.

Mites have been a persistent infectious disease affecting both humans and animals since ancient times. In veterinary clinics, the primary approach for treating and managing mite infestations has long been the use of chemical acaricides. However, the widespread use of these chemicals has resulted in significant problems, including drug resistance, drug residues, and environmental pollution, limiting their effectiveness. To address these challenges, researchers have shifted their focus towards natural products that have shown promise both in the laboratory and real-world settings against mite infestations. Natural products have a wide variety of chemical structures and biological activities, including acaricidal properties. This article offers a comprehensive review of the acaricidal capabilities and mechanisms of action of natural products like plant extracts, natural compounds, algae, and microbial metabolites against common animal mites.

Long-term immunogenicity after single and booster dose of a live attenuated hepatitis A vaccine: results from 8-year follow-up.

Live, attenuated hepatitis A vaccines are used widely in China but there is uncertainty regarding the persistence of vaccine-induced anti-HAV antibodies after single dose and booster dose administrated at month 12. A large scale clinical trial to evaluate the live, attenuated hepatitis A vaccine was conducted in Hebei province between 1996 and 1999. Five years after the trials, children in single dose and booster dose groups were bled and followed. Seventy two percent (61/85) of children who received a single trial dose had detectable anti-HAV antibodies for 96 months (GMC at 96 months: 89.0 mIU/mL). In the booster group 98% (48/49) children remained anti-HAV positive with GMC of 262.8 mIU/mL at month 96. The reinjection with live attenuated HAV vaccine can elicit a booster effect. Results from single dose group seems not to support the need for booster doses of live attenuated hepatitis A vaccine in immunocompetent individuals regarding the persisting anti-HAV and anamnestic response of a single dose vaccine. Continued monitoring of anti-HAV antibodies is needed for a rational hepatitis A immunization strategy in China.

Incidence of diarrhea caused by rotavirus infections in rural Zhengding, China: prospective, population-based surveillance.

Rotavirus is the pathogen most commonly associated with severe gastroenteritis in young children in the People's Republic of China, yet there are few population-based data on the incidence of rotavirus infection. The present study investigated the burden of rotavirus diarrhea and rotavirus infections in rural China, according to age. Population-based surveillance was used to study the incidence of rotavirus infection among children <5 years of age in 4 townships of Zhengding County, Hebei Province, China. The total population in the catchment area in 2002 was 75,630 individuals, including 2997 children aged <5 years. Stool samples were obtained and were tested for rotavirus antigen by use of an enzyme-linked immunosorbent assay. During 2002, a total of 2010 cases of diarrhea were detected among children <5 years of age. The incidence of treated cases of diarrhea was 671 cases/1000 children/year for children <5 years of age, and it was highest for children <12 months of age (1467 cases/1000 children/year). The estimated incidence of rotavirus infection was 151 cases/1000 children/year for children <5 years of age. The highest incidence of rotavirus infection was among children aged 1-2 years (340 cases/1000 children/year). Widespread immunization of children against rotavirus before 6 months of age should be considered for the control of rotavirus diarrhea.

Occurrence of shigellosis in the young and elderly in rural China: results of a 12-month population-based surveillance study.

In 2002, population- and treatment center-based surveillance was used to study the disease burden of shigellosis in rural Hebei Province in the People's Republic of China. A total of 10,105 children with diarrhea or dysentery were enrolled. Infants were treated most frequently for diarrhea (1,388/1,000/year) followed by children < or = 5 years old (618/1,000/year). Shigellosis was treated most often in children 3-4 years old (32/1,000/year) and people > 60 years of age (7/1,000/year). Fifty-six percent (184 of 331) Shigella isolates were detected in patients who had non-bloody diarrhea. Shigella flexneri was identified in 93% of 306 isolates. The most common S. flexneri serotypes were 1a (34%), X (33%), and 2a (28%). More than 90% of the Shigella isolates were resistant to cotrimoxazole and nalidixic acid, but remained susceptible to ciprofloxacin, norfloxacin, and gentamicin. Widespread resistance to antibiotics adds urgency to the development and use of vaccines to control shigellosis.

A community-based cluster survey on preferences for treatment of diarrhoea and dysentery in Zhengding county, Hebei province, China.

Passive surveillance on the burden of disease due to diarrhoea will underestimate the burden if families use healthcare providers outside the surveillance system. To study this issue, a community-based cluster survey was conducted during October 2001 in the catchment area for a passive surveillance study in Zhengding county, a rural area of northern China. Interviews were conducted at 7 randomly-selected households in each of 39 study villages. The respondents indicated where they sought initial care for cases of diarrhoea or dysentery among children or adults. In the absence of diarrhoea and dysentery cases in the household in the preceding four weeks, the respondents were asked about healthcare use for a hypothetical case. Overall, 80% (95% confidence interval [CI] 67-93%) would chose the village clinic, 11% village pharmacy (95% CI 1-22%), 4% township hospital (95% CI -1-10%), 4% self-treatment (95% CI 1-8%), and 1% county hospital (95% CI 0-2%). Approximately, 84% of patients would seek treatment for diarrhoea and dysentery at centres participating in passive surveillance, suggesting that passive surveillance will provide a relatively accurate assessment of burden of diarrhoea in Zhengding county.

[Effectiveness of post-exposure prophylaxis using live attenuated hepatitis Alpha vaccine (H(2) strain) among schoolchildren].

OBJECTIVE: To observe the efficacy of emergency immunization to abort hepatitis Alpha outbreak using live attenuated hepatitis Alpha vaccine. METHODS: During an outbreak of hepatitis Alpha in a village in Zhengding County, Hebei Province, one dose of live attenuated hepatitis Alpha vaccine (H(2) strain) was administered to 92 schoolchildren of two primary schools in that village on a voluntary basis, and 189 schoolchildren who were not vaccinated were used as controls. Their serum specimens were collected 3 times at different time points (0 and 18 days after the vaccination and 40 days after the appearance of the last hepatitis Alpha case). The total antibody and IgM of hepatitis Alpha were examined by ELISA. Clinical observation was made to discover whether new case appeared. The rates of seroconversion and hepatitis Alpha in susceptibles between vaccinated and unvaccinated groups were compared. RESULTS: The new infection rate of hepatitis Alpha during the 18 days after vaccination was 5.43% in the vaccinated group and 7.43% in the control group (P > 0.05). The prevalence rate was 0 in both groups (P > 0.05). The new infection rate of hepatitis Alpha during the period from the 18th day after vaccination to the 40th day after the appearance of the last case was 2.41% in the vaccinated group and 3.21% in the control group (P > 0.05). CONCLUSION: The live attenuated hepatitis Alpha vaccine can not provide post-exposure protection against infection of hepatitis Alpha virus during the outbreak.

[Immediate immunological effect of China-made recombinant hepatitis B vaccine expressed by transgenic Chinese hamster ovary cell line].

OBJECTIVE: To understand the protective efficacy of China-made recombinant hepatitis B vaccine expressed by transgenic Chinese hamster ovary cell line among newborns. METHODS: 2 969 newborns in seven townships in Zhengding County, Hebei Province, were vaccinated with 10 microgram x 3 doses of China-made recombinant hepatitis B vaccine expressed by transgenic Chinese hamster ovary cell line according to the 0 - 1 - 6 month schedule from 1 January 1997 to 31 August 1999. The newborns were to be vaccinated with the first dose within 24 hours after they were born. 1906 serum samples were selected in April 2000 to detect the hepatitis B infection markers, including HBsAg, HBsAb and HbcAb by RIA kits. RESULTS: 2 783 of the 2 969 newborns (93.74%) were vaccinated with three doses, 2 833 of them (95.42%) were vaccinated with the first dose within 24 hours after they were born. The anti-HBs positive rate was 98.25% (S/N >/= 2.1) or 94.26% (S/N >/= 10.0), and the geometric mean titer (GMT) value of antibody was 77.64 within the first year after the whole course vaccination. Then the antibody level decreased gradually with the lapse of time. The HBsAb positive rate was 92.31% (S/N >/= 2.1) or 68.96% (S/N >/= 10.0), and GMT value was 22.86 within the third year after vaccination. The HBsAg positive rates remained less than 1%, the HBcAb positive rates and HBV infection rates remained 1% approximately 3% within 3 years after vaccination. CONCLUSION: The protective efficacy of China-made recombinant hepatitis B vaccine is satisfactory.

A 12-year cohort study on the efficacy of plasma-derived hepatitis B vaccine in rural newborns.

AIM:To understand the anti HBs persistence and the long-term preventive efficacy in rural newborns after vaccination with plasma-derived hepatitis B vaccine.METHODS:In the time of expanded program on immunization (EPI), the newborns were vaccinated with 10&mgr;gcenter dot3 doses of hepatitis B vaccine and 762 newborns who were HBsAg negative after primary immunization were selected for cohort observation from 1986 to 1998. Their serum samples were detected qualitatively and quantitatively for hepatitis B infecting markers, including HBsAg, anti-HBs and anti-HBc by SPRIA Kits. The annual HBsAg positive conversion rate was counted by life-table method.RESULTS:(1)The anti-HBs positive rate was 94.44% for the babies born to HBsAg negative mothers and 84.21% for those born to HBsAg positive mothers in the 1st year after immunization, and dropped to 51.31% and 52.50% in the 12th year respectively.GMT value was dropped from 31.62 to 3.13 and 23.99 to 3.65 in the 2nd to the 12th year respectively. There was a marked drop in GMT at the 3rd to the 5th year, and in anti HBs positive rate at the 9th to the 10th year. (2) In the period of 12 years observation, the person-year HBsAg positive conversion rates were 0.12% (5/4150.0) in newborns born to HBsAg negative mothers and 0.20% (1/508.0) in those born to HBsAg positive mothers, and none of the HBsAg positive converted children became HBsAg chronic carriers. Compared with the baseline before immunization, the protective rates were 97.19% and 95.32% respectively.CONCLUSION:The protective efficacy of plasma-derived hepatitis B vaccine persisted at least 12 years, and a booster dose seems not necessary within at least 12 years after the primary three-doses immunization to newborns born to HBsAg negative mothers.