Aldicarb as a Cause of Food Poisoning—Louisiana, 1998 FREE

MMWR. 1999;48:269-271

Cholinesterase-inhibiting pesticides (i.e., organic phosphates and carbamates), widely used in agriculture, can cause illness if they contaminate food or drinking water. Aldicarb, a regulated carbamate pesticide, is highly toxic, and the U.S. Environmental Protection Agency (EPA) requires applicators to be trained and certified. This report describes a foodborne outbreak of aldicarb poisoning that occurred when improperly stored and labeled aldicarb was used mistakenly in food preparation.

On July 19, 1998, 20 employees attended a company lunch prepared from homemade foods. Shortly after eating, several persons developed neurologic and gastrointestinal symptoms. Ten visited a hospital emergency department, and two were hospitalized. On July 20, a hospital infection-control nurse reported the incident to the Louisiana Office of Public Health, which then investigated the outbreak.

Investigators interviewed all 20 lunch participants about illness and foods eaten during the meal; 14 (70%) reported gastrointestinal or neurologic symptoms. The most common gastrointestinal symptoms were abdominal cramps (13 [93%]), nausea (13 [93%]), and diarrhea (12 [86%]). Neurologic symptoms included dizziness (13 [93%]), sweating (12 [86%]), muscle fasciculations (12 [86%]), eye twitching (eight [57%]), and blurred vision (six [43%]). Illness lasted a median of 4 hours (range: 1-8 hours). Median time between ingestion of food and onset of symptoms was 45 minutes (range: 40 minutes-3 hours). The heart rate of one of the two persons hospitalized was 20 beats per minute on arrival at the emergency department, but his heart rate increased after treatment with atropine. The second person was hospitalized for an increased and irregular heart beat that responded to treatment with digitalis.

The lunch consisted of pork roast, boiled rice, cabbage salad, biscuits, and soft drinks. Only the cabbage salad was associated with illness. Of the 16 persons who ate the cabbage salad, 14 became ill (attack rate: 88%); the four persons who had not eaten the cabbage salad did not develop symptoms (attack rate: 0%, p=0.003, Fisher's exact test).

The employee who prepared the cabbage salad reported mixing two 1-lb bags of precut, prepackaged cabbage in a bowl with vinegar and ground black pepper. The black pepper came from a can labeled "black pepper" that he had found 6 weeks before the lunch in the truck of a deceased relative. This black pepper had not been used by the employee for food preparation before the company lunch. The cabbage salad was prepared the night before the lunch and stored in the refrigerator until it was brought to work and served at approximately 11 AM.

The contents of the black pepper container were tested for organophosphate and carbamate pesticides. High-performance liquid chromatography identified the granules in the container as 13.7% aldicarb, the pesticide TEMIK® 15G.* A 6-g portion of cabbage salad contained 272.6 parts per million (ppm) of aldicarb.

The deceased owner of the pepper can had been a crawfish farmer. After its investigation, the Louisiana Department of Agriculture and Forestry believed the crawfish farmer had used aldicarb on bait to prevent destruction of his crawfish nets, ponds, and levees by wild dogs and raccoons. The source of the TEMIK® 15G could not be determined despite the department's extensive traceback effort.

TA Farley, MD, L McFarland, DrPH, State Epidemiologist, Infectious Disease Epidemiology Section, Louisiana Dept of Health and Hospitals; J McClelland, Louisiana Dept of Agriculture. Health Studies Br, Div of Environmental Hazards and Health Effects, National Center for Environmental Health; Div of Applied Public Health Training, Epidemiology Program Office; and an EIS Officer, CDC.

Aldicarb (2-methyl-2-[methylthio] propionaldehyde O-[methylcarbamoyl] oxime) is one of the most potent pesticides used in the United States. It is absorbed rapidly through the gut and, in liquid form, through intact skin.¹ As a cholinesterase inhibitor, it increases parasympathetic nervous system activity. Common symptoms of poisoning include malaise, dizziness, sweating, nausea, diarrhea, and muscle weakness; blurred vision and muscle spasms also can occur. EPA has placed aldicarb in its highest acute toxicity category.

Aldicarb is classified as a restricted-use pesticide and can be sold to and applied by trained certified applicators only. Applicators are required to wear personal protective equipment (i.e., coveralls, waterproof gloves, chemical-resistant footwear and headgear, and protective eyewear). In cases of aldicarb poisoning, atropine sulfate is the antidote of choice and can be supplemented by treatment of symptoms and rapid removal of the toxin (e.g., by induced vomiting).²

The 272.6 ppm of aldicarb found in a 6-g cabbage salad sample was enough to be toxic to humans. Each person who had eaten the salad would have consumed approximately 17 mg of aldicarb if equal amounts of salad had been eaten. A 150-lb (70-kg) adult would have ingested 0.2 mg of aldicarb per kg of body weight, nearly 10 times the lowest observed effect level for subclinical blood cholinesterase depression (0.025 mg per kg body weight). Blood levels as low as 0.0011 mg per kg body weight have been associated with poisoning in humans.³ In addition, cabbage and vinegar, both acidic substances, are less effective than alkaline substances at breaking down aldicarb to less toxic chemical compounds.

In addition to occupational exposures,⁴ aldicarb poisoning has resulted from unintentional or suicidal ingestion of aldicarb illegally used as a rodenticide⁵ and from eating contaminated watermelons^6- 7 and cucumbers.⁷ The largest pesticide-related foodborne outbreak in the United States occurred in 1985 when 1373 persons reported becoming ill after eating watermelons grown in soil treated with aldicarb; 78% of these persons had probable or possible pesticide-related illnesses.⁶ The median amount of aldicarb sulfoxide eaten per person in that outbreak was approximately 0.027 mg per kg body weight.⁸ Aldicarb residues have been detected in ground water and drinking water wells,⁹ but studies of the clinical implications of these exposures have been inconclusive.¹⁰ EPA has developed tolerance levels for aldicarb residues on food or animal feed and a maximum contaminant level for aldicarb in drinking water (0.003 mg/L).

Nonprofessional pesticide users and certified applicators should be alert to the adverse effects of pesticides on human health and to the risks involved in distributing pesticides to noncertified persons. In addition, the public should be reminded to store pesticides and other hazardous chemicals exclusively in containers that are clearly and correctly labeled and secured by safety caps. Finally, health-care providers and public health officials should keep in mind that food poisoning might result from pesticide or other chemical contamination as well as from infectious organisms.

*Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services or CDC.

MMWR. 1999;48:289-292

2 tables omitted

In Massachusetts during 1989-1996, perinatal health indicators such as infant mortality, teen birth rate, and maternal smoking during pregnancy decreased steadily; however, low birthweight (LBW) (i.e., <2500 g [<5 lbs, 8 oz]) rates increased consistently.¹ During this same period, the multiple-birth rate (i.e., number of twins and higher order multiple births per 100 live births) increased from 2.5% in 1989 to 3.5% in 1996. Massachusetts has the highest multiple-birth rate in the United States.^2- 3 Multiple births are more likely to result in LBW infants.² To determine the effect of changes in the rate of multiple births on LBW rates and to characterize women who have multiple births, the Massachusetts Department of Public Health examined data on births in Massachusetts during 1989-1996. This report summarizes the results of this analysis, which indicate that the increase in LBW rates in Massachusetts was associated with changes in the rate of multiple births, especially among older, better educated women.

Data were derived from birth certificates of infants born to women who resided in Massachusetts during 1989-1996. Plurality is classified as singleton, twin, and triplets-plus (i.e., multiple births of three or more infants). Two categories of maternal education were analyzed: high school education or less and four or more years of college. Adjusted LBW rates were calculated by applying the plurality-specific LBW rate in a given year to the plurality distribution in 1989. The adjusted LBW rate can be interpreted as the LBW rate in a given year had the plurality distribution been the same as in 1989. The difference between the adjusted and unadjusted LBW rates indicates the effect of the change in the distribution of plurality on LBW rates.

From 1989 to 1996, the LBW rate for singletons remained constant at 4.8%. However, the proportion of twins increased from 2.4% to 3.3%, and the LBW rate among twins increased slightly from 45.8% to 48.2%. The largest plurality-specific increase in births was among triplets-plus, which increased from 0.1% of all births in 1989 to 0.2% in 1996. The LBW rate for triplets-plus did not change substantially from 1989 through 1996, ranging from 84% to 92%.

The unadjusted LBW rate increased 8% during 1989-1996. However, when LBW rates were adjusted for the increase in multiple births, LBW rates for 1989 and 1996 were the same (5.9%).

In 1989, multiple-birth rates by maternal education level were similar: for women with a high school education or less, the rate was 2.4%, compared with 2.5% for women with four or more years of college. From 1989 to 1996, the proportion of multiple births to women with high school education or less increased from 2.4% to 2.8%, and the proportion of multiple births to women with four or more years of college increased from 2.5% to 4.2%. Among women aged ≥35 years and with four or more years of college, the proportion of multiple births increased from 3.2% to 5.8%. Although the overall number of births in Massachusetts decreased 12% from 1989 to 1996, the number of multiple births increased 24%. Among women aged ≥35 years, the number of multiple births more than doubled. From 1989 through 1996, unadjusted LBW rates for infants born to women aged <35 years with a high school education or less declined slightly from 7.1% to 7.0%; among women aged <35 years with four or more years of college, the LBW rate increased 22%, from 4.1% to 5.0%. Among women aged ≥35 years, LBW rates increased 27% among less educated women (7.8% to 9.8%) and 30% (5.0% to 6.5%) among more educated women.

BB Cohen, DJ Friedman, Z Zhang, EB Trudeau, Bur of Health Statistics, Research and Evaluation; DK Walker, M Anderka, S Fogerty, S Franklin, Bur of Family and Community Health, Massachusetts Dept of Public Health. PA McKenna, March of Dimes, Boston, Massachusetts. Div of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.

The findings in this report indicate that the increase in the proportion of multiple births is directly responsible for the increase in crude LBW rates in Massachusetts from 1989 to 1996. These findings are consistent with national data that indicate state LBW rates are affected by twin birth rates.⁴

This analysis highlights two issues. First, although multiple births constitute a small proportion of all live-born infants, the large increase in multiple births substantially influences trends in LBW. Routine birthweight surveillance trend data should be adjusted for, or stratified by, plurality. Second, the characteristics of mothers giving birth to LBW infants changed during this time period. For example, in 1989, 59% of LBW infants in Massachusetts were born to women who had a high school education or less. By 1996, 43% of LBW infants were born to women who had a high school education or less. From 1989 to 1996, the proportion of LBW infants born to women aged >35 years doubled (from 11% to 22%).

The increase in multiple births and LBW rates, particularly among older women, may result from increased use of fertility drugs and assisted reproduction technologies.⁵ In Massachusetts in 1996, based on new data recorded on Massachusetts birth certificiates, fertility drugs or assisted reproduction technologies were used by 13% of mothers with multiple-birth deliveries, compared with 0.7% of mothers with singleton births. Massachusetts law, which requires insurance companies, health-maintenance organizations, and medical assistance to cover medically necessary expenses of infertility diagnosis and treatment, and the state's aging birthing population may have increased the use of assisted reproduction technologies.⁶ In addition, better educated women may be more sophisticated users of reproductive assistance and have the financial resources for the additional costs of fertility treatment.

The findings in this report are subject to at least two limitations. First, newly collected data on birth certificates about use of fertility drugs and assisted reproduction technologies may be underreported. Second, other factors that may affect change in LBW (e.g., smoking) were not included in this analysis.

The public health implications for targeting services for this emerging LBW infant population and their mothers are substantial. Multiple gestation increases morbidity risks for infants and mothers^2,7 and mortality risks for infants.⁸ Programs such as high-risk infant identification, congenital anomaly surveillance, and delivery of early intervention services must be reevaluated as a result of these changes in the birthing population.

MMWR. 1999;48:271-274

2 tables omitted

In Romania and other countries, therapeutic injections have been associated with transmission of hepatitis B and C viruses, human immunodeficiency virus type 1 (HIV-1), and other bloodborne pathogens.^1-6 During 1997-1998, acute hepatitis B was associated with recent injections in Romanian children aged <5 years.³ Injection-associated bloodborne pathogen transmission occurs when infection-control practices are inadequate, and overuse of injections to administer medications might increase opportunities for transmission. To estimate the frequency of therapeutic injections and to describe the attitudes and practices of adults about injections to administer medications, local health departments in Romania surveyed the general population of four districts (Hunedoara, Iasi, Mures, and Prahova [1997 combined population: 2.8 million]) in June 1998. This report summarizes results from these surveys, which indicate that injections are used frequently to administer medications in Romania.

A cluster sample of 300 households in each of the four viral hepatitis sentinel surveillance districts was surveyed, totaling 1200 households.⁷ All household members, or adult guardians for children aged <15 years, were interviewed in person to collect information about age, sex, and number of vaccine-related or therapeutic injections received during June 1, 1997-May 31, 1998. To evaluate attitudes and practices regarding therapeutic injections among adults, one randomly selected person aged ≥18 years in each household was interviewed. Therapeutic injections were defined as injections or infusions administered through intradermal, subcutaneous, intramuscular, or intravenous routes and not given for vaccination or recreational drug use.

Of the 3676 survey participants (mean age: 38 years; range: 0-98 years; 48% male), 365 (10%) reported receiving at least one vaccine-related injection (median: two injections; range: one-15 injections) for a total of 988 injections; this proportion was inversely related to age, with 60% of children aged <5 years and 2% of persons aged ≥45 years receiving vaccine-related injections. At least one therapeutic injection (median: eight injections; range: one-735 injections) was reported by 1334 (36%) participants for a total of 19,630 injections. The proportion of participants who reported receiving a therapeutic injection did not vary significantly across all age groups but was lower for males than for females (prevalence ratio=0.8; 95% CI=0.7-0.9). Of the 19,630 therapeutic injections, 643 (3%) were intravenous infusions, and 18,987 (97%) were other injections. Most (18,249 [96%]) of these other injections were administered by health-care workers; of these, 11,020 (56%) were administered in outpatient clinics or in homes, 6236 (32%) in hospitals, and 993 (5%) in dental settings.

Of the 1197 persons aged ≥18 years (mean age: 49 years; range: 18-95 years; 45% male) interviewed about attitudes and practices regarding therapeutic injections, 891 (74%) believed injectable medications were "stronger" than oral medications. A smaller proportion preferred injected over noninjected medications to treat fever (28%), "common cold" (29%), diarrhea (17%), and for vitamin supplementation (42%). In addition, 32% of the participants indicated they would ask their physician for an oral medication if an injection were prescribed, and 10% stated they would ask their physician for an injectable medication if an oral medication were prescribed. Syringes were reported in 46% (95% Confidence interval [CI]=42%-51%) of households, of which 96% (95% CI=94%-98%) were new disposable syringes.

O Sfetcu, D Cremenasiu, S Circiumaru, Hunedoara Health District; M Barhala, R Florescu, E Duca, Iasi Health District; A Cojan, E Marialaky, MM Yanku, Mures Health District; M Irimia, A Dobrescu, Prahova Health District; M Popa, N Ion-Nedelcu, D Craciun, Dept of Preventive Medicine, Ministry of Health, Romania. Hepatitis Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; and an EIS Officer, CDC.

By extrapolating the findings in this survey to the population of Romania (1997 population: 22.5 million), an estimated average of 5.3 therapeutic injections are administered annually per capita, and approximately 120 million therapeutic injections are administered each year. For each vaccine-related injection, survey respondents received 20 therapeutic injections.

In Romania, a substantial proportion of adults preferred injected medication for treatment of conditions for which injections generally are not indicated, including fever, acute upper respiratory tract infection, vitamin supplementation, and diarrhea. However, this proportion did not exceed 42% and suggests that Romanians may not insist on injectable medications for common illnesses. In other countries, reasons reported for demand for therapeutic injections include beliefs that the pain of the injection is a marker of efficacy, that medications are more effective when entering the body percutaneously, and that injections represent advanced technology.⁸

In addition to patient preference for injections, physicians' prescribing practices also might affect the observed high use of therapeutic injections. In other countries, reported reasons for overuse of injections by health-care providers include a desire to observe therapy, belief that efficacy is greater when medications are injected, and occasionally, financial incentives to use injections.⁸ Population focus groups conducted in 1998 in Romania indicate that patients trust their physicians' advice about medical treatments and would not seek a second opinion if an injection were not prescribed (CDC, unpublished data, 1998). Additional information is needed on the determinants of physicians' prescribing practices in Romania to promote the use of alternatives to injected medications.

The findings in this report are subject to at least two limitations. First, review of survey participants' medical records could not be used to validate self-reports of injections. Participants' inability to recall accurately the number of injections received during the 12-month referent period, particularly participants who had been hospitalized, may have led to underestimation of the total number of injections received. Second, data are from only four districts in Romania and may not be representative of the entire country.

Because knowledge about and sufficient resources for proper infection-control practices for safe injections are limited in Romania (CDC, unpublished data, 1998), overuse of therapeutic injections increases opportunities for bloodborne pathogen transmission among patients. Accordingly, programs to improve injection safety should focus on reducing the number of therapeutic injections administered. Such programs might be developed more effectively if initial studies are conducted to estimate the frequency of injections in the population and identify determinants of injection use among patients and health-care providers.

References: 8 available