A novel coronavirus associated with severe acute respiratory syndrome.

BACKGROUND: A worldwide outbreak of severe acute respiratory syndrome (SARS) has been associated with exposures originating from a single ill health care worker from Guangdong Province, China. We conducted studies to identify the etiologic agent of this outbreak. METHODS: We received clinical specimens from patients in seven countries and tested them, using virus-isolation techniques, electron-microscopical and histologic studies, and molecular and serologic assays, in an attempt to identify a wide range of potential pathogens. RESULTS: None of the previously described respiratory pathogens were consistently identified. However, a novel coronavirus was isolated from patients who met the case definition of SARS. Cytopathological features were noted in Vero E6 cells inoculated with a throat-swab specimen. Electron-microscopical examination revealed ultrastructural features characteristic of coronaviruses. Immunohistochemical and immunofluorescence staining revealed reactivity with group I coronavirus polyclonal antibodies. Consensus coronavirus primers designed to amplify a fragment of the polymerase gene by reverse transcription-polymerase chain reaction (RT-PCR) were used to obtain a sequence that clearly identified the isolate as a unique coronavirus only distantly related to previously sequenced coronaviruses. With specific diagnostic RT-PCR primers we identified several identical nucleotide sequences in 12 patients from several locations, a finding consistent with a point-source outbreak. Indirect fluorescence antibody tests and enzyme-linked immunosorbent assays made with the new isolate have been used to demonstrate a virus-specific serologic response. This virus may never before have circulated in the U.S. population. CONCLUSIONS: A novel coronavirus is associated with this outbreak, and the evidence indicates that this virus has an etiologic role in SARS. Because of the death of Dr. Carlo Urbani, we propose that our first isolate be named the Urbani strain of SARS-associated coronavirus.

Anthelminthic drug safety and drug administration in the control of soil-transmitted helminthiasis in community campaigns.

Helminth infections are now recognised as being a major health priority worldwide. Morbidity due to these infections can be controlled at a reasonable cost by means of periodic chemotherapy using effective drugs. Deworming campaigns targeted at high risk groups, such as school-age children, pre-school children and women of child-bearing age, are the mainstay of the control strategy launched by WHO. Anthelminthic drugs can be delivered effectively through the school system, women's associations or other community-based interventions, each of which often lack health personnel supervision. The safety of anthelminthic drugs is, therefore, of paramount importance and side effects have to be recognised and monitored, especially when generic drugs are widespread. Four anthelminthic drugs are considered to provide appropriate single dose treatment against soil-transmitted helminthiasis: albendazole, levamisole, mebendazole and pyrantel. Side effects, at the dosage recommended for deworming, have been described as negligible and self-limiting. However, a limited number of reports have associated more severe adverse reactions to the distribution of anthelminthic medicines. Even if the available information cannot confirm a cause-effect relationship, it is essential that these effects are known. Ministries of Health can then set up efficient and safe delivery, monitoring and referral systems, in order to minimise the risk and maximise the benefit of periodic anthelminthic chemotherapy in communities where soil-transmitted helminthiasis is endemic.

The control of human (neuro)cysticercosis: which way forward?

Taenia solium cysticercosis, and its public health and economic consequences, appears to be a growing problem in poor areas of Africa, Asia and Latin America where people eat pork and traditional pig husbandry is practiced (and expanding). Its burden is counted in terms of human disease (mainly neurocysticercosis related epilepsy) and economic losses, in a context of both commercial and traditional subsistence pig farming. Although substantial fragmentary information seems to be available from local settings, national and global burdens due to T. solium cysticercosis are still to be comprehensively assessed. With regard to control, several strategies have been checked out at a small or medium scale and have proven to be successful. Yet, no intervention programmes have been implemented so far at the national level with proven success. Although T. solium cysticercosis is considered to be a potentially eradicable disease, there is no evidence yet that it is feasible and recommendable to envisage this within a reasonable time frame. However, it appears realistic to aim for the rapid definition of a simple package of interventions, which can routinely be carried out by existing services and structures, and will give an optimal, long-term return in terms of burden relief. Also, a number of international initiatives and opportunities currently exist in which a more pro-active attitude towards the control of T. solium cysticercosis can be integrated and promoted. Commitment of both national and local authorities to control the disease needs to be convincingly solicited and, as for most zoonotic diseases, an interdisciplinary approach is essential.

Control of echinococcosis and cysticercosis: a public health challenge to international cooperation in China.

Echinococcosis, both cystic and alveolar, and Taenia solium cysticercosis are the most serious zoonotic cestodoses worldwide. Because of the emerging importance of these diseases in China, several international workshops and meetings were held in this country from 1998 to 2001. Based on round table discussions in Chengdu 2000, the proposal of a strategy to control echinococcosis and cysticercosis has been prepared in China. It includes a comprehensive approach based on a careful analysis of the local situations (particularly concerning the particularities of the cycle, ecology, and ethology of the animal hosts, and behavioral characteristics of the population at risk), the use of newly developed tools both in animals and human (immunology, molecular biology, and imaging), and the association of the traditional control measures (control of slaughtering, antiparasitic treatment and control of the definitive hosts, and health education) with more recent developments such as vaccination of the intermediate hosts. Plans on for the control of echinococcosis and cysticercosis in China are summarized.

Mekong malaria. II. Update of malaria, multi-drug resistance and economic development in the Mekong region of Southeast Asia.

In an expansion of the first Mekong Malaria monograph published in 1999, this second monograph updates the malaria database in the countries comprising the Mekong region of Southeast Asia. The update adds another 3 years' information to cover cumulative data from the 6 Mekong countries (Cambodia, China/Yunnan, Lao PDR, Myanmar, Thailand, Viet Nam) for the six-year period 1999-2001. The objective is to generate a more comprehensive regional perspective in what is a global epicenter of drug resistant falciparum malaria, in order to improve malaria control on a regional basis in the context of social and economic change. The further application of geographical information systems (GIS) to the analysis has underscored the overall asymmetry of disease patterns in the region, with increased emphasis on population mobility in disease spread. Of great importance is the continuing expansion of resistance of P. falciparum to antimalarial drugs in common use and the increasing employment of differing drug combinations as a result. The variation in drug policy among the 6 countries still represents a major obstacle to the institution of region-wide restrictions on drug misuse. An important step forward has been the establishment of 36 sentinel sites throughout the 6 countries, with the objective of standardizing the drug monitoring process; while not all sentinel sites are fully operational yet, the initial implementation has already given encouraging results in relation to disease monitoring. Some decreases in malaria mortality have been recorded. The disease patterns delineated by GIS are particularly instructive when focused on inter-country distribution, which is where more local collaborative effort can be made to rationalize resource utilization and policy development. Placing disease data in the context of socio-economic trends within and between countries serves to further identify the needs and the potential for placing emphasis on resource rationalization on a regional basis. Despite the difficulties, the 6-year time frame represented in this monograph gives confidence that the now well established collaboration is becoming a major factor in improving malaria control on a regional basis and hopefully redressing to a substantial degree the key problem of spread of drug resistance regionally and eventually globally.