[Risk factors for antitubercular drug resistance in Chiapas, Mexico]. / Factores de riesgo para resistencia a drogas antifímicas en Chiapas, México.

OBJECTIVES: To determine risk factors for antibiotic resistance in patients with pulmonary tuberculosis in four Health Jurisdictions of the state of Chiapas. MATERIAL AND METHODS: A case-control study was carried out in patients diagnosed by acid fast smear during 1992. A questionnaire was applied which included variables related to the diagnosis, treatment and follow-up of the patients. Sputum samples were collected for culture and sensitivity tests. A case of drug-resistant pulmonary tuberculosis was defined as the presence of culture colonies showing resistance to one or more drugs. The control group was patients with negative smears and cultures or positive cultures for M. tuberculosis sensitive to the specific drugs. RESULTS: Of the total of 18 individuals reported to have positive cultures, 13 (72.2%) were resistant to one or more drugs. Resistance to two or more drugs was found in 10 of them of which three were resistant to five antituberculosis drugs. The most frequent resistance was to isoniazid (77%). Risk factors for resistance encountered in this patient population were monotherapy (OR = 34.2), abandonment of treatment (OR = 6.86), a prolonged period of illness (OR = 6.40), delay in diagnosis and a history of prior therapy (OR = 28.3). CONCLUSIONS: The high proportion of patients resistant to antituberculosis therapy poses a public health problem and is a clear consequence of the problems arising from inadequate treatment.

[Outbreaks of food poisonings of microbial and parasitic origins]. / Brotes de toxiinfecciones alimentarias de origen microbiano y parasitario.

In order to know the agents and foods related more frequently with food-borne disease outbreaks, we reviewed all the outbreaks studied between 1980 and 1989 by the National Laboratory of Public Health. A total of 79 outbreaks of food-borne diseases of microbial origin were reviewed. The causative agent was identified in 50 (73%) outbreaks. Twenty-four per cent of the outbreaks occurred in parties, 10.3 per cent in school or nurseries, 8.6 per cent in restaurants and 8.6 per cent in hospitals. Staphylococcus aureus was the most common agent, causing 48.2 per cent of the outbreaks. Salmonella enterica was involved in 34 per cent of them. The most frequent serovar was typhimurium. Foods involved were: cheese in 29.3 per cent of the cases; cakes in 15.5 per cent; cooked meat in 15.1 per cent; milk in 13.8 per cent; and fish and seafood in 7.0 per cent of the cases. Since the number of studied incidents represents only a small proportion of all the outbreaks occurring in the country, the constant exchange of information among the laboratories which work on the problem and the promotion of the health care team are necessary in order to improve the epidemiologic surveillance systems and the study and prevention of food-borne disease and food poisoning outbreaks.

[Poisoning by paralytic molluscan toxins in Oaxaca]. / Intoxicaciones por toxina paralizante de molusco en Oaxaca.

Toxic Red Tides are caused by marine dinoflagellates which synthesize neurotoxins that accumulate in bivalve mollusks. Upon ingestion, these shellfish can cause paralysis and death. During the month of December, 1989, 99 cases of Paralytic Shellfish Poisoning in the areas of Salina Cruz and Huatulco, Oaxaca, were reported; three of which died. The majority of the cases involved the ingestion of oysters and clams. A short time later, the Red Tide was reported appearing. One hundred and fifteen seafood samples were analyzed through a biologic test in mice to determine the quantity of saxitoxin. Oysters and clams showed levels reaching 4 000 U.R. Laboratory analysis of seawater found very high quantities of Gimnodinium catenatum and Gonyaulax catenella. The control measures consisted of the prohibition of the harvest and sale of all bivalve mollusks as well as a public warning to avoid the consumption of such shellfish.

[Coffee tree cultivation and the social history of onchocerciasis in Soconusco, Chiapas state, Mexico]. / Cafeticultura e historia social de la oncocercosis en el Soconusco, estado de Chiapas, México.

Due to the social and ecological changes that have taken place in the region of Soconusco, Chiapas, Mexico, the coffee tree growth economy (established in the latter part of the last century) has been an important factor in the transmission of onchocerciasis. The optimum ecological conditions for the growth of the coffee tree coincide with those of the disease's growth rate vector; the mobilization of migrant workers for the cultivation and gathering of coffee beans, plus changes in the natural environment, are elements which explain the disease's distribution in the different regions. The origin of the disease in Chiapas may be due to the migration of coffee plantation workers from Guatemala in search of land in which to settle. Social changes occurring after the Agrarian Distribution (land distributions that occurred in 1918 and 1940) caused an intensification and modernization in the areas of cultivation which in turn caused a decline in the disease's growth rate vector. This, together with standard of living improvements and control measures against the disease, explain why the problem in these regions has decreased considerably. The use of ivermectin as a new therapy paves the way for better disease control in the future. Nevertheless, in the smaller locations occupied by middle and poor class farmers, where coffee bean cultivation is just commencing and still in a rudimentary form, onchocerciasis and other diseases continue to present serious health problems.