A SHORT HISTORY OF OCCUPATIONAL DISEASE: 1. LABORATORY-ACQUIRED INFECTIONS.

Laboratory-acquired infections are as old as laboratories themselves. As soon as the culture of microorganisms was introduced, so too was their transfer to laboratory workers. It is only in relatively recent history that such infections have been fully understood, and methods of spread and their prevention or avoidance developed. This paper endeavours to provide an overview of the history of laboratory-acquired infection and the steps taken, particularly in the UK, for its prevention.

Tuberculosis por inoculación / Inoculation tuberculosis

Una bacterióloga sufrió un accidente por punción con una aguja con jeringa que contenía una cepa de Mycobacterium tuberculosis en un dedo de la mano. La zona de la punción se inflamó y la expresión del dedo 15 días después del accidente arrojó una gota de pus que puesta al microscopio permitió observar 3 bacilos ácido-alcohol resistentes con la técnica de Ziehl-Neelsen. Se diagnosticó tuberculosis por inoculación accidental y fue tratada como tal. Se discuten las características de este caso encuadrado como tuberculosis cutánea, cuando se produce como infección exógena por inoculación directa.

A bacteriologist suffered a puncture accident while manipulating a Mycobacterium tuberculosis strain, affecting a finger. The involved area swelled and a drop of pus came out after pressure on the finger 15 days afterwards. This was stained by Ziehl-Neelsen technique, and three acid-fast bacilli were observed. Tuberculosis was diagnosed, and proper treatment was started. We discuss the case, classified as cutaneous tuberculosis produced by exogenous infection through accidental direct inoculation.

Percutaneous exposure resulting in laboratory-acquired leptospirosis -- a case report.

A screw-capped glass tube containing a Leptospira culture accidentally broke and the laboratory worker who was handling the tube sustained a cut on his hand. The wound was flooded with the culture. The culture was that of strain MG 347 belonging to serovar Australis recovered from a patient, and it had undergone 52 passages in Ellinghausen McCullough Johnson Harris medium. The laboratory worker developed a headache 21 days after the accident and became febrile the next day. He was hospitalized for 5 days and was treated initially with doxycycline and later with ciprofloxacin. A blood sample collected on the second day of illness, after starting doxycycline therapy, yielded leptospires and the isolate, HZ 651, was identified as serovar Australis. Monoclonal antibody patterns and randomly amplified polymorphic DNA fingerprinting patterns of the isolate and strain MG 347 were identical, thus indicating that HZ 651 and MG 347 were clonal.

Accidental infection of laboratory worker with vaccinia virus.

We report the accidental needlestick inoculation of a laboratory worker with vaccinia virus. Although the patient had previously been vaccinated against smallpox, severe lesions appeared on the fingers. Western blot and polymerase chain reaction-restriction fragment length polymorphism were used to analyze the virus recovered from the lesions. The vaccinia virus-specific immunoglobulin G levels were measured by enzyme-linked immunosorbent assay. Our study supports the need for vaccination for laboratory workers that routinely handle orthopoxvirus.

Zoonoses of occupational health importance in contemporary laboratory animal research.

In contemporary laboratory animal facilities, workplace exposure to zoonotic pathogens, agents transmitted to humans from vertebrate animals or their tissues, is an occupational hazard. The primary (e.g., macaques, pigs, dogs, rabbits, mice, and rats) and secondary species (e.g., sheep, goats, cats, ferrets, and pigeons) of animals commonly used in biomedical research, as classified by the American College of Laboratory Animal Medicine, are established or potential hosts for a large number of zoonotic agents. Diseases included in this review are principally those wherein a risk to biomedical facility personnel has been documented by published reports of human cases in laboratory animal research settings, or under reasonably similar circumstances. Diseases are listed alphabetically, and each section includes information about clinical disease, transmission, occurrence, and prevention in animal reservoir species and humans. Our goal is to provide a resource for veterinarians, health-care professionals, technical staff, and administrators that will assist in the design and on-going evaluation of institutional occupational health and safety programs.

Cryptogenic rabies, bats, and the question of aerosol transmission.

Human rabies is rare in the United States; however, an estimated 40,000 patients receive rabies postexposure prophylaxis each year. Misconceptions about the transmission of rabies are plentiful, particularly regarding bats. Most cases of human rabies caused by bat variants have no definitive history of animal bite. Three hypotheses are proposed and reviewed for the transmission of rabies from bats to human beings. They include nonbite transmission (including aerosol transmission), the alternate host hypothesis (an intermediate animal host that acquires rabies from a bat and then transmits rabies to human beings), and minimized or unrecognized bat bites. Nonbite transmission of rabies is very rare, and aerosol transmission has never been well documented in the natural environment. The known pathogenesis of rabies and available data suggest that all or nearly all cases of human rabies attributable to bats were transmitted by bat bites that were minimized or unrecognized by the patients.

Niveles de bioseguridad en microbiología: la norma IRAM 80059 / Biosafety levels in microbiology: the IRAM 80059 norm

Se analiza la Norma IRAM 80059 cuyo objeto es determinar las características de los niveles de bioseguridad necesarios para operar con distintos microorganismos. Se fijan cuatro niveles de bioseguridad, describiendo las características de los mismos, estableciendo la correspondencia no sólo con el nivel de riesgo individual y comunitario inherente al microorganismo (de acuerdo a la conocida clasificación de la OMS), sino también con el tipo de operación que se realiza con ellos. Se concluye que ésta Norma constituye un aporte que permitirá clarificar numerosas situaciones en el trabajo microbiológico, que hasta ahora eran motivo de discusión

[Surveillance of laboratory based infections by biological and medical analyses: review of the literature]. / La surveillance des maladies infectieuses basée sur les laboratoires d'analyses biologiques et médicales: revue de la littérature.

Infectious disease surveillance is one of the priorities of public health programmes. This review aims to describe laboratory-based infection surveillance systems. The following surveillance networks are described: the Belgian microbiology network, AIDS surveillance in Philadelphia, EPIBAC, and the Salm-Net network. Laboratory-based surveillance provides the advantage of constituting an easily accessible computerised data bank that allows for studying age-old tendencies and evaluating the effectiveness of certain prevention programmes. The main inconveniences remain with the difficulty of eliminating duplications as well as the lack of clinical information. These difficulties can be surmounted by improving communication systems among the diverse participants in the network with electronic mail. Such surveillance systems will facilitate information exchanges at both the national and international level.

Brucellosis: an occupational hazard for medical laboratory personnel. Report of five cases.

Five cases of laboratory-acquired infection with Brucella melitensis are reported. This pathogen is highly contagious when handled in the laboratory. Clinicians should alert technologists when brucellosis is suspected so that specimens are handled under the most stringent safety measures. Serological surveys and instructions of laboratory workers regarding the clinical diversity of the disease are helpful for early recognition of secondary cases. On the other hand, clinicians should consider brucellosis in medical laboratory workers with unexplained signs and symptoms.

Laboratory-acquired malaria, leishmaniasis, trypanosomiasis, and toxoplasmosis.

Because of renewed interest in parasitic diseases, increasing numbers of persons in clinical and research laboratories have the potential for exposure to parasites and therefore are at risk for acquiring parasitic infections. In this review of laboratory-acquired parasitic infections, we concentrate on protozoan diseases that frequently have been reported to be laboratory acquired: malaria, leishmaniasis, trypanosomiasis (American and African), and toxoplasmosis. These diseases can be severe, even fatal, and may be difficult to diagnose. Many laboratorians who have acquired these diseases did not recall having had an accident. Of those with recognized accidents, needlestick injuries were the most common. Laboratories should have established protocols for handling specimens that may contain viable organisms and for responding to laboratory accidents.

Brucellosis: imported and laboratory-acquired cases, and an overview of treatment trials.

Following the successful eradication of Brucella abortus infection in cattle, human brucellosis in England and Wales has become an uncommon imported disease. Culture of the organism presents a major laboratory hazard, and difficulties in identification may occur using a biochemical test-strip method. An overview of recent treatment trials of brucellosis indicates that regimens combining streptomycin and doxycycline are associated with a higher success rate (judged by the frequency of treatment failure and relapse following therapy) than combinations of rifampicin and doxycycline.

Comparative study of human and rabbit cell infection with cell-free HTLV-I.

Infection of human and rabbit cells with cell-free HTLV-I was studied by PCR analysis. Both human and rabbit PBL were infected similarly by cell-free virus of both human and rabbit cell origin. Cells were infected with the cell-free virus without prior treatment and regardless of the concentration of the culture supernatant containing the virus. Human and rabbit cell lines were also infected similarly by the cell-free virus, the proviral DNA persisting for more than two months. The culture supernatants of HTLV-I-producing cells could thus be a potential cause of laboratory infections.