SARS infection by TCM?
According to recent publications two Chinese research teams, aided by Australian and American colleagues, were able to identify a SARS-like Corona virus (SL-CoV) in certain bat species. This virus is very similar to the SARS-virus affecting humans (1,2). This has lead to the conclusion that bats are probably also a host to the SARS-virus affecting humans.
One of the research teams (1) isolated a SL-CoV in 23 out of 59 rectal smears from wild bats belonging to the Rhinolophus sinicus species, home to the Hong Kong area. They found an 88% similarity in this virus's nucleotides and the SARS-virus's nucleotides. The second team (2) examined nine other bat-species, which they had collected in their natural habitats in South China. They found high concentrations of SARS-antibodies in three of those species: Rhinolophus pearsoni, R. pussilus, and R. macrotis. The genome of one of the viruses found in a faecal sample was 92% identical to the SARS-virus.
Up to now SARS-like viruses were especially likely to be found in civets sold at animal markets in South China. However, the assumption that these animals were the source for the infection became improbable when it was discovered that the virus was seldom found in domesticated civets or those living in the wild. One theory to explain this phenomenon is that the proximity of the civets and other animals in these markets was responsible for the infection jumping from one species to another. This makes sense, since the virus tends to dramatic genetic changes that lead to greater adaptability to another species. Bats are sold at South Chinese animal markets together with other species. Bat meat is considered a delicacy in China. Bat faeces (verspertilionis faeces, ye ming sha) are used in Chinese Medicine. The online edition of the German Deutsche ÃÂrzteblatt published 30. September 2005 suggested a direct risk by printing the headline "SARS as a result of traditional Chinese Medicine? "(3). Does Verspertilionis faeces pose a direct health threat?
According to Bensky/Clavey/StÃ¶ger (4) the officinal species used in TCM is Vespertilio superans THOMAS. However, other species are actually used more often, among them those from the genus Rhinolophus: Rhinolopus ferrumequinum. This particular one is not identical to the above-mentioned species in which the SARS-like virus was identified. A SARS-infection of this bat species is nevertheless possible until proven otherwise. A directly resulting health risk is, however, difficult to imagine. According to reports the SARS-virus can survive up to 4 days in faeces (human faeces) (5). Verspertilionis faeces only plays a minor role in Europe. The raw, unprocessed feces cannot be obtained in Germany; this medicinal is only available as granulate from a small number of suppliers. The virus is inactivated at 56ÃÂ°C, an infection through this processed drug is thus almost impossible. We recommend that for legal and psychological reasons and until the risk has been thoroughly assessed, use of this medicinal should be avoided.
The consumption of bat meat is altogether a different matter; it is conceivable that you can contract SARS through a transmission from traces of faeces or other animal bits of a freshly slaughtered or frozen bat to human.
On the same topic, there is evidence for a positive effect of Chinese herbal prescriptions in SARS-prophylaxis (6): in a controlled clinical study during the SARS-epidemic in Hong Kong, a group of 1063 employees in one hospital were given a Chinese herbal prescription for two weeks. The control group consisted of the 36.111 employees of 10 other hospitals which did not receive the Chinese herbs. While none of those taking the Chinese medicine became infected, 0.4% of those in the control group contracted SARS (p=0.014). The prescription consisted of a mixture of modifications of the formulas sang ju yin and yu ping feng san. The main ingredients were: Mori Folium (sang ye), Chrysanthemi Flos (ju hua), Armeniacae Semen (xing ren), Forsythiae Fructus (lian qiao), Menthae Herba (bo he), Platycodi Radix (jie geng), Glycyrrhizae Radix (gan cao), Phragmitis Rhizoma (lu gen), Astragali Radix (huang qi), Saposhnikoviae Radix (fang feng), Isatitis Folium (da qing ye) und Scutellariae Radix (huang qin).
- Lau SKP, Woo PCY, Li KSM et al. Severe acute respiratory syndrome coronavirus-like virus in Chinese horseshoe bats. PNAS 102(39): 14040-14045
- Li W, Shi Z, Yu M et al. Bats are natural reservoirs of SARS-like coronaviruses. Science express 29.09.2005. www.scienceexpress.org
- Bensky D, Clavey S and StÃÂ¶ger E. Chinese Herbal Medicine. Materia Medica. 3th ed. Seattle: Eastland Press, 2004
- WHO (2003)http://www.who.int/csr/sars/survival_2003_05_04/en/
- Lau JTF, Leung PC, Wong ELY et al. (2005). The use of an herbal formula by hospital care workers during the severe acute respiratory syndrome epidemic in Hong Kong to prevent severe acute respiratory syndrome transmission, relieve influenza-related symptoms, and improve quality of life: a prospective cohort study. J Altern Complement Med 11: 49-55