Cluster of postinjection abscesses related to corticosteroid injections and use of benzalkonium chloride.

Benzalkonium chloride (BC) is an unreliable disinfectant. A matched case-control study and environmental investigation were conducted to determine the cause of and risk factors for a cluster of postinjection abscesses at a private medical clinic where BC was used as a disinfectant. Twenty-eight case-patients who had an abscess at the injection site were matched with 126 control patients who had received an intramuscular injection at the clinic on the same day. Risk factors for abscess development in a multivariable logistic model were corticosteroid injection and being female. All case-patients had received a corticosteroid injection from a multidose vial. Cultures of abscesses from 20 of 23 case-patients grew Pseudomonas aeruginosa. Cultures of BC prepared at the clinic also grew P aeruginosa, suggesting that BC was the source of infection. Injection site cleaning with BC did not appear to be the route of infection since use of BC at the time of injection was not associated with abscess development. A more likely route of infection was injection of contaminated corticosteroid from multidose vials that could have been inoculated with pseudomonads via needle puncture after vial septa were wiped with contaminated BC. Benzalkonium chloride should not be used to clean injection vial septa or injection sites.

Evidence against person-to-person transmission of hantavirus to health care workers.

Unusual, primarily pulmonary, manifestations of hantaviral illness occurring in the southwestern United States raised the possibility of person-to-person transmission of a recently recognized hantavirus, Sin Nombre virus. To determine whether such transmission had occurred among health care workers (HCWs) exposed to patients with confirmed hantavirus pulmonary syndrome, we evaluated HCWs who had cared for patients with hantavirus pulmonary syndrome or who had processed specimens from these patients. Information about exposure to these patients and about recent illnesses was obtained via a standardized questionnaire. Serum specimens were tested for IgM and IgG antibodies to hantaviruses with use of ELISAs. Of the 396 HCWs, 266 (67%) reported that they had been exposed to patients with hantavirus pulmonary syndrome or to their body fluids or that they had processed laboratory specimens from these patients. Although 108 (27%) of the HCWs reported fever, myalgias, or respiratory illnesses during the 3 months before the serum specimens were obtained, hantavirus antibodies were not detected in any HCW. These data suggest that person-to-person transmission of Sin Nombre virus is unlikely to occur in health care settings.

Epidemiologic linkage of rodent and human hantavirus genomic sequences in case investigations of hantavirus pulmonary syndrome.

Sin Nombre virus (SNV) causes the zoonotic disease hantavirus pulmonary syndrome (HPS). Its mechanisms of transmission from rodent to human are poorly understood. It is possible that specific genetic signature sequences could be used to determine the probable site of each case-patient's exposure. Environmental assessments suggested 12 possible sites of rodent exposure for 6 HPS patients. Rodents were captured at 11 of the 12 sites and screened for SNV infection within 2 weeks of the patient's diagnosis. Viral sequences amplified from tissues of rodents at each site were compared with those from case-patients' tissues. Rodents bearing viruses with genetic sequence identity to case-patients' viruses across 2 genomic segments were identified in 4 investigations but never at >1 site. Indoor exposures to rodents were especially common at implicated sites. By distinguishing among multiple possible sites of exposure, viral genotyping studies can enhance understanding of the conditions associated with infection by SNV.

Overcoming barriers and reaping the benefits of surveillance for infectious diseases: the New Mexico perspective.

Surveillance for disease is one of the cornerstones of public health practice in the United States. Surveillance, particularly for infectious diseases, has allowed the detection of outbreaks and provided for the long-term monitoring of disease incidence. In New Mexico, acquired immunodeficiency syndrome (AIDS) surveillance is characterized as one of the most comprehensive surveillance systems for an infectious disease to be found anywhere. The success of this system is largely a result of state and federal resources and a good partnership with the AIDS/human immunodeficiency virus health care providers. Surveillance for Haemophilus influenzae type b (Hib) has demonstrated a remarkable decline in disease incidence in the state especially since the use of second generation Hib capsular polysaccharide conjugate vaccine. In contrast, surveillance for hepatitis A has demonstrated a significant public health problem that is largely not being addressed by current control measures.

Evaluation of the magnitude of the 1993 hantavirus outbreak in the southwestern United States.

In May 1993, an outbreak of hantavirus pulmonary syndrome (HPS) in the southwestern United States was caused by the previously unrecognized Sin Nombre virus (SNV). Most HPS patients had an influenza-like prodrome, followed by rapid onset of pulmonary edema (fatality rate, 52%). To define the magnitude of the outbreak, patients with milder illnesses who sought medical care in the outbreak area during the outbreak period were assessed for infection with SNV. Of 299 study subjects, 43 had illnesses similar to the HPS prodrome. One laboratory finding, thrombocytopenia, was highly discriminatory between non-HPS patients (1%) and confirmed HPS patients (71%; P < .001) during the prodrome phase. No study subject had serologic evidence (IgM antibodies) of recent SNV infection. Five had IgG titers consistent with a previous hantavirus infection: 3 of these 5 were among the 43 patients who had illnesses similar to the HPS prodrome (P < .05). These data provide evidence that mild illness is rarely caused by SNV.

Firearms in New Mexico.

To determine the prevalence of firearm ownership and storage practices in New Mexico, we did a random-digit-dialing survey of New Mexico residents in October 1991. Of 200 households surveyed, 79 (40%) had 1 or more firearms in the home. Rural households were more likely than urban households to have firearms (44% versus 30%), and households with annual incomes of greater than $25,000 were more likely to have a firearm than households with incomes of $25,000 or less (41% versus 33%). Household firearm ownership did not vary with the presence of young (< 15 years old) children (38% with children versus 41% without). Handguns were generally owned for self-protection, and rifles were owned for hunting. Of households with firearms, 24% stored them unsafely (unlocked and loaded or unloaded but with ammunition nearby), including 21% of households with young children. Of the households with handguns only, 40% stored these firearms unsafely compared with 13% of those with rifles only. The prevalence of gun ownership in New Mexico is similar to that reported in national surveys; handguns are stored less safely than rifles; and the presence of young children in the home does not appear to improve firearm storage safety.

Pedestrian and hypothermia deaths among Native Americans in New Mexico. Between bar and home.

OBJECTIVE: To determine the nature of excess injury mortality among Native Americans in New Mexico. DESIGN: Retrospective review of death certificates for deaths from unintentional injuries. SETTING: The state of New Mexico. SUBJECTS: New Mexico residents who died of unintentional injuries between January 1, 1980, and December 31, 1989. MAIN OUTCOME MEASURE: Cause-specific mortality rates. RESULTS: Over half of the excess mortality from all unintentional injuries among Native Americans resulted from hypothermia and from pedestrian-motor vehicle crashes. New Mexico Native Americans were nearly eight times more likely to die in pedestrian--motor vehicle crashes and were 30 times more likely to die of hypothermia compared with other New Mexico residents. At death, 90% of those Native Americans tested were highly intoxicated (median blood alcohol concentrations of 0.24 and 0.18 g/dL [corrected] for pedestrian and hypothermia deaths, respectively). Despite the fact that most Native Americans in New Mexico live on reservations, most deaths occurred at off-reservation sites in border towns and on roads leading back to the reservation. CONCLUSIONS: The possession and sale of alcohol is illegal on many Native American reservations. This policy forces Native Americans who want to drink to travel long distances to obtain alcohol. These data suggest that this policy is also the likely explanation for the markedly increased risk of death from hypothermia and pedestrian-motor vehicle crashes in this population.

Eosinophilia-myalgia syndrome. A clinical case series of 21 patients. New Mexico Eosinophilia-Myalgia Syndrome Study Group.

We reviewed 21 cases of eosinophilia-myalgia syndrome to describe the range of clinical findings in these patients. Most patients were women (20 [95%]) and middle-aged (mean, 46 years) and had taken the food supplement L-tryptophan (95%). All cases involved eosinophilia (eosinophil count, greater than or equal to 2.0 x 10(9)/L) and incapacitating myalgias. Fourteen (88%) of the 16 patients tested had mild liver function abnormalities. Aldolase levels were abnormal in all patients tested. Muscle biopsies were done in five patients; four showed eosinophilic perimyositis, and one had interstitial inflammation. No physical finding was pathognomonic or universal, but muscle tenderness, tachycardia, and rash were the most common signs found during physical examinations. Seven patients were treated with prednisone, and six showed improvement in muscle pain and a decrease in eosinophilia. The cause of this disorder is still unknown.

L-tryptophan and eosinophilia-myalgia syndrome in New Mexico.

On Oct 30, 1989, the New Mexico Health and Environment Department learned of 3 patients with eosinophilia and severe myalgia who had been taking L-tryptophan. Further review of these and similar cases led to the initial recognition of the eosinophilia-myalgia syndrome (EMS) epidemic. To elucidate the apparent association between L-tryptophan-containing products (LTCPs) and EMS a case-control study was done. The case definition was unexplained peripheral eosinophilia (2000/microliters or more) and incapacitating myalgia. Cases were found through review of white blood cell counts from May 1 to Oct 31, 1989, in nine medical laboratories in New Mexico. 11 cases and 22 matched controls were interviewed for information on symptoms and other clinical findings, on the use of LTCPs, and on potential confounding factors. All 11 cases (100%) used LTCPs compared with only 2 controls. These findings led to a ban on the sale of LTCPs in New Mexico, followed by a nationwide recall of such preparations in the United States.

Effects of the 65-mph speed limit on rural interstate fatalities in New Mexico.

As a result of federal legislation passed in April 1987, New Mexico was the first state to resume a 65-mph speed limit on rural Interstate highways. We compared the rates of fatal crashes before and after the speed limit change. The rate of fatal crashes in the 1 year after the speed limit was increased was 2.9 per 100 million vehicle-miles traveled, compared with a predicted rate of 1.5 per 100 million vehicle-miles based on the trend of the 5 previous years. When fatal crashes that occurred after the speed limit change were compared with fatal crashes in the 5 previous years, there was no difference in the mean age and sex of the at-fault drivers, mean age and sex of the victims, seat belt use by the victims, or alcohol involvement of the crashes. The increase in fatal crashes can be attributed to an increase in fatal single-vehicle crashes. Vehicles on rural Interstates are traveling at greater rates of speed and a larger proportion of vehicles are exceeding the 65-mph speed limit. The benefits associated with the 65-mph speed limit should be weighed against the increased loss of lives.

Injury mortality in New Mexico's American Indians, Hispanics, and non-Hispanic whites, 1958 to 1982.

New Mexico has extraordinarily high injury mortality rates. To better characterize the injury problem in New Mexico, we calculated proportionate injury mortality and age-adjusted and age-specific injury mortality rates for the state's 3 major ethnic groups--American Indians, Hispanics, and non-Hispanic whites. According to death certificate data collected from 1958 to 1982 and US population census figures, age-adjusted mortality rates for total external causes varied widely between the sexes and among the ethnic groups. Males in each ethnic group consistently had higher average annual age-adjusted external mortality rates than females. Injury mortality rates for American Indians of both sexes were 2 to 3 times higher than those for the other New Mexico ethnic groups. Motor vehicle crashes were the leading cause of death from injury for all 3 groups. Homicide accounted for twice the proportion of injury death in Hispanic compared with non-Hispanic white males (12.5% and 6.1%, respectively), while the proportion of males dying of suicide was highest in non-Hispanic whites. Deaths from excessive cold and exposure were leading causes of injury mortality for American Indians, but these causes were not among the leading causes of injury mortality for Hispanics or non-Hispanic whites. We conclude that the minority populations in New Mexico are at high risk for injury-related death and that the major causes of injury mortality vary substantially in the state's predominant ethnic populations.

Child restraint law effects on motor vehicle accident fatalities and injuries: the New Mexico experience.

The New Mexico State Legislature passed a child restraint law applicable to children less than 5 years of age that became effective in June 1983. To evaluate the effectiveness of this law, we analyzed traffic accident data for New Mexico from January 1981 through September 1984. During this period, there were 20,972 children younger than 5 years of age in motor vehicle accidents. Restraint usage increased for this age group from a low of about 10% in 1981 to more than 40% in 1984 (P less than 10(-6)). Unrestrained children younger than 5 years of age were five times more likely to be killed and two times more likely to be injured than restrained children. Analysis of motor vehicle accident fatality and injury rates pre- and post-law revealed a 33% reduction in motor vehicle accident fatality rates and a 12.6% reduction in nonfatal injury rates for children younger than 5 years. We conclude that child restraint devices are effective in reducing motor vehicle accident fatalities and injuries in young children and the child restraint law has been effective in increasing child restraint usage and in reducing childhood death and injury in New Mexico.

Antibiotic resistance patterns during aminoglycoside restriction.

When amikacin first became available its use was restricted to prevent the emergence of resistant strains of gram-negative bacilli to this new agent. Gentamicin was the aminoglycoside most widely used at this time, and the incidence of gentamicin-resistant bacteria was 14%, while only 2.4% were resistant to amikacin. For a period of 15 months gentamicin use was restricted, and amikacin was used almost exclusively. Amikacin use was associated with a fall in the incidence of gentamicin-resistant bacteria to 9.2% (p less than .00005), while amikacin resistance remained unchanged at 2.2% (NS). During a period of 21 months after all aminoglycoside restrictions were lifted, gentamicin use again increased, and was accompanied by a return of gentamicin resistance to the baseline level of 15.3%. During this period, amikacin resistance also increased to 4.0% (p less than .0000001) but was due primarily to an increase in resistant Pseudomonas aeruginosa. Escherichia coli was the most frequently isolated gram-negative bacillus during all three periods, and it remained sensitive to both antibiotics regardless of the drug in use. In contrast, P. aeruginosa showed a high level of resistance to gentamicin, which fell when this antibiotic was restricted, only to return to a high level with reinstitution of gentamicin. While there was also an increase in amikacin resistant strains of P. aeruginosa with unrestricted aminoglycoside use, there was no apparent shift in the pattern of aminoglycoside modifying enzymes among a small random selection of amikacin-resistant bacteria. Impaired uptake of antibiotic was the predominant mechanism responsible for P. aeruginosa resistance among strains that did not produce aminoglycoside acetyltransferase (AAC)(6').

Staphylococcal nasal carriage and subsequent infection in peritoneal dialysis patients.

Thirty patients undergoing long-term home-based peritoneal dialysis were monitored for 13 months for carriage of Staphylococcus aureus in the nares and for the development of infectious complications. The patients could be divided into three groups with regard to S aureus carriage: chronic, intermittent, and noncarriers. Twenty-five episodes of peritonitis and 20 episodes of catheter exit-site infections occurred during 268 patient-months of observation. Staphylococcus aureus accounted for eight episodes of peritonitis and 12 episodes of exit-site infection. Chronic and intermittent carriers of S aureus were found to be at higher risk of development of infection than noncarriers.