Kamis, 25 Agustus 2011


chapter 2 Failures in the distribution of antisera to places where they are needed are another factor contributing to the gravity and complexity of this public health problem. In some instances, antisera are held in the main cities, where rabies and envenomings are rare, instead of being distributed to peripheral health clinics in rural areas where dog and snake bites, and scorpion stings are frequent. This refl ects defective distribution planning which is associated with a lack of coordination between those who understand the epidemio-logical pattern of the disease and those responsible for the antiserum distribution. As a consequence, antivenoms are sent to places where there are no snake bites or where the par ticular antivenoms are inef fective. Fur thermore, rural health facilities may lack suffi cient antivenoms to treat even a single case of envenoming, because the health authorities are uninformed of treatment protocols.


Ensuring adequate supply of antisera will inevitably incur some wastage, as products become expired. Pharmacies should have suffi cient stocks to cover contingencies such as seasonal epidemics of snake bites. In Brazil, where approximately 4% of all antivenom is misused (wrong species or non-venomous snake bite), double the expected antivenom requirement (cases x average dose) is supplied to health centres. Therefore, an adequate distribution policy of antiserum demands some form of epidemiological surveillance programme and close communication between clinicians, other health workers, epidemiologists, governmental procurement offi ces and manufacturers. Also, inadequate storage and transportation of antisera may result in physical destruction of vials and ampoules (e.g. by freezing of liquid antisera). The lack of an adequate cold chain may result in deterioration and ineffi cacy of liquid antisera and cold chain facilities created for other health needs (e.g. vaccines) should be used more thoroughly. Decisions on distribution of liquid and freeze-dried antisera, when both formulations are available, should be based on careful and detailed analysis of the prevailing conditions in each region and health clinic facilities. The design of effective strategies for distributing antisera is thus an essential component of any global effort to confront this serious crisis.

Inadequate access to therapeutic antisera is also related to the lack of health facilities in many rural regions of Africa, Asia, Latin America and New Guinea, together with a lack of adequate transportation of patients to the nearest health post. This diffi cult and dangerous situation becomes even worse when rural populations are uninformed about how to proceed when someone is bitten by a possibly rabid dog or a snake, or is stung by a scorpion. Community public education campaigns are needed to address this problem.

Besides the inadequate supply, distribution and accessibility of safe and effective antisera, another major issue is the lack of training of health workers on how to use these products and how to conduct appropriate clinical management of these medical emergencies. In many countries, medical and nursing school curricula do not include the treatment of rabies and envenomings. These subjects are also omitted from the training programmes implemented in rural hospitals where these conditions are common. The development of national and regional guidelines for the treatment of envenomings, based on consensus views, has been largely neglected; exceptions include the Guidelines from the WHO Regional Offi ce for South East Asia (SEARO) (46). Efforts need to be made for a wide distribution of guidelines among physicians and nurses in rural hospitals. The end-result of all these defi ciencies is a dearth of standardized and adequate treatment protocols and, consequently, the existence of a signifi cant diversity in clinical practice and a profusion of empirically-derived protocols.

Another problem associated with antivenom treatment is the uncertainty about the criteria for rational use and initial and repeated dosage. In some hospitals, a small dose of antivenom is given routinely to every patient presenting a snake bite, irrespective of whether there is any evidence of envenoming. This practice squanders scarce resources and unnecessarily exposes unenvenomed people to the risk of antivenom reactions. In other situations, excessive doses are administered without justifi cation, thus wasting this precious commodity. The results of any programme of medical staff training and improved access to antisera should be monitored by continuous surveillance of the appropriateness of antisera usage.


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