Laboratory-acquired malaria, leishmaniasis, trypanosomiasis, and toxoplasmosis

Needlestick injuries in dentistry: Time to revisit

BACKGROUND

Blood-borne pathogens (BBPs) are infectious microorganisms that are found in human blood and can cause diseases in humans. Health care workers such as physicians, surgeons, nurses, dentists, dental students, dental assistants, laboratory technicians, personnel handling infectious waste, and other health care employees are at increased risk of exposure to these pathogens. Percutaneous injuries from needles or other sharp objects are the major sources of BBPs in the workplace. Needlestick injuries (NSIs) have the most potential to transmit and have the easiest mode of transmission of BBPs.

TYPES OF STUDIES REVIEWED

The authors searched electronic databases (PubMed, Web of Science, Google Scholar, Scopus, Embase, MEDLINE-Ovid) for studies and articles focused on the various aspects of NSIs, their possible causes, prevention, and management protocols.

RESULTS

There is a lack of literature on the global prevalence of NSIs among dental practitioners and underreporting of NSIs by clinicians. The authors also found that dental students and inexperienced practitioners were the most vulnerable. They found apparent inconsistencies in guidelines and recommendations from various regulatory and statutory agencies in charge of limiting and managing NSIs.

CONCLUSION

The most significant occupational risks for health care workers globally are NSIs. Dentists are recognized as one of the high-risk groups for exposure to NSIs. Although the reporting rate was noticeably low, the frequency of NSIs among dental students was alarmingly high.

PRACTICAL IMPLICATIONS

Appropriate and succinct training of dental health care workers is crucial for prevention and management of NSIs. It is recommended that dentists familiarize themselves with recommendations from such agencies and organizations as the Center for Disease Control and Prevention, Occupational Safety and Health Administration, and American Dental Association.

Patterns of Systemic Disease Diagnoses among Medical Professionals in Taiwan: Statistical Analysis and Data Mining

INTRODUCTION

Although high-risk work environments and heavy workload expose medical professionals to long-term risks of disease, no comprehensive analysis has been conducted on the corresponding risks of diseases to each type of medical professionals. This study pre-analyzed the risks of medical professionals in developing various systemic diseases in Taiwan to provide a comprehensive examination of the differences between each type of systemic disease.

METHODS

From the secondary databases of 2002-2013, 15,407 medical professionals were selected for analysis. A chi-squared test and logistic regression were performed to identify the relationship between types of medical professionals and systemic diseases. The life trajectories of diagnosis sequence of the medical professionals were illustrated accordingly.

RESULTS

The physicians were the most vulnerable to infectious, parasitic, and digestive diseases. This was possibly associated with their work characteristics and occupational risks.

CONCLUSION

According to the life trajectories, all types of the medical professionals exhibited a similar trend in the orders of risks to each type of systemic disease, which suggests that their work environment exposes them to real risks of health hazard.

Biological Risks and Laboratory-Acquired Infections: A Reality That Cannot be Ignored in Health Biotechnology

Advances and research in biotechnology have applications over a wide range of areas, such as microbiology, medicine, the food industry, agriculture, genetically modified organisms, and nanotechnology, among others. However, research with pathogenic agents, such as virus, parasites, fungi, rickettsia, bacterial microorganisms, or genetic modified organisms, has generated concern because of their potential biological risk - not only for people, but also for the environment due to their unpredictable behavior. In addition, concern for biosafety is associated with the emergence of new diseases or re-emergence of diseases that were already under control. Biotechnology laboratories require biosafety measures designed to protect their staff, the population, and the environment, which may be exposed to hazardous organisms and materials. Laboratory staff training and education is essential, not only to acquire a good understanding about the direct handling of hazardous biological agents but also knowledge of the epidemiology, pathogenicity, and human susceptibility to the biological materials used in research. Biological risk can be reduced and controlled by the correct application of internationally recognized procedures such as proper microbiological techniques, proper containment apparatus, adequate facilities, protective barriers, and special training and education of laboratory workers. To avoid occupational infections, knowledge about standardized microbiological procedures and techniques and the use of containment devices, facilities, and protective barriers is necessary. Training and education about the epidemiology, pathogenicity, and biohazards of the microorganisms involved may prevent or decrease the risk. In this way, the scientific community may benefit from the lessons learned in the past to anticipate future problems.

Selected Zoonoses

Human risks of acquiring a zoonotic disease from animals used in biomedical research have declined over the last decade because higher quality research animals have defined microbiologic profiles. Even with diminished risks, the potential for exposure to infectious agents still exists, especially from larger species such as nonhuman primates, which may be obtained from the wild, and from livestock, dogs, ferrets, and cats, which are generally not raised in barrier facilities and are not subject to the intensive health monitoring performed routinely on laboratory rodents and rabbits. Additionally, when laboratory animals are used as models for infectious disease studies, exposure to microbial pathogens presents a threat to human health. Also, with the recognition of emerging diseases, some of which are zoonotic, constant vigilance and surveillance of laboratory animals for zoonotic diseases are still required.

The Cytotoxic T Lymphocyte Antigen-4 +49A/G Single Nucleotide Polymorphism Association With Visceral Leishmaniasis

Background:

Several lines of evidence approve that innate and adaptive immunity play key roles in the defense against visceral leishmaniasis (VL). The polymorphism within the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene alters its expression.

Objectives:

The main aim of this study was to evaluate the polymorphism within the +49 position of the CTLA-4 gene of Iranian patients with VL in comparison with healthy controls.

Materials and Methods:

In this cross-sectional study, 88 patients with clinical presentations of VL, who were seropositive for Leishmania (group 1), 86 patients without clinical presentations but seropositive (group 2), and 115 healthy controls (group 3) were assessed with respect to the CTLA-4 +49A/G polymorphism, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The anti-Leishmania antibody titration was evaluated using an immunofluorescence method.

Results:

Our results indicated that both CTLA-4 +49A/G polymorphisms were significantly associated with VL.

Conclusions:

According to the results, the polymorphisms within the +49 position of CTLA-4 can be associated with VL and may be considered as risk factors for the disease.

Evaluation of FcγRIIIB-NA1/NA2 Polymorphism in Visceral Leishmaniasis

BACKGROUND

Several lines of evidence demonstrating that innate and adaptive immunity play important roles in the defense against visceral leishmaniasis (VL). A polymorphism within the FcγRIIIB gene can lead to the expression of three variants of NA1, NA2, and the combined one (NA1/NA2) which alters affinity of IgG to its receptor.

OBJECTIVES

The main aim of this study was to evaluate the FcγRIIIB-NA1/NA2 polymorphism in the FcγRIIIB gene of VL patients in comparison to healthy controls.

PATIENTS AND METHODS

In this cross-sectional study, three groups; 54 seropositive patients with clinical presentation of VL (group 1), 104 seropositive patients without clinical presentation (group 2), and 104 healthy controls (group 3) were evaluated with respect to the FcγRIIIB-NA1/NA2 polymorphism using a PCR-SSP method. The titration of anti-leishmania antibodies was analyzed using an immunoflorescence technique.

RESULTS

Our results indicated that polymorphisms within the FcγRIIIB gene (that lead to the expression of the NA1/NA2 isoforms) are significantly associated with VL. The results demonstrated that the genotype heterozygotic for FcγRIIIB-NA1/NA2 expression was significantly increased in VL patients, group 1 when compared to groups 2 and 3. Conversely, there is a decrease in homozygous NA1 and NA2 genotypes in VL patients; however, the overall frequency of NA1 and NA2 alleles appear similar across the three cohorts examined.

CONCLUSIONS

According to our results, it is likely that the increased frequency of the FcγRIIIB-NA1/NA2 genotype is associated with impaired immune responses against VL and its subsequent clearance from the patient.

Transepidermal elimination in cutaneous leishmaniasis: a multiregional study

BACKGROUND

Transepidermal elimination has been documented in a myriad of infectious diseases; however, its occurrence in cutaneous leishmaniasis has not been evaluated.

METHODS

Skin biopsies (n = 212) with cutaneous leishmaniasis in Lebanon (n = 46), Syria (n = 53), Saudi Arabia (n = 45) and Pakistan (n = 68) were evaluated. Clinical data collected included age, gender, eruption type (papule, nodule, verrucous or scar), duration and anatomic location. Histopathologically, multiple parameters were recorded including Ridley's parasitic index and pattern, transepidermal elimination, interface changes, ulceration and necrosis. Transepidermal elimination was defined as the presence of amastigotes in the epidermis in all layers, limited to the basal layer or present in a perforating plug. All cases were confirmed by polymerase chain reaction (PCR) analysis followed by restriction fragment length polymorphism analysis for molecular subspeciation.

RESULTS

Leishmania tropica was identified in 88.2% and Leishmania major in 11.8% of all cases. Transepidermal elimination was observed in 28.3% of cases (29 perforating plug, 19 all layers and 12 basal layer) with a significant prevalence of L. major in this group (35 vs. 2%, p < 0.001). Cases with transepidermal elimination were associated with interface changes and higher parasitic index (p < 0.001) but not with an increased ulceration rate (p > 0.05). Multivariate analysis showed that transepidermal elimination was independently predicted by L. major [OR (95% confidence interval) = 80 (9-712); p < 0.001], parasitic index [OR = 3.4 (2.1-5.3); p < 0.001], interface changes [OR = 6.24 (2.2-17.8); p < 0.001] and necrosis [OR = 0.2 (0.1-0.8);p = 0.026].

CONCLUSIONS

We report the largest multiregional cutaneous leishmaniasis series with a 28.3% documented transepidermal elimination incidence of which 48% were perforating plug; a significant prevalence of L. major was also identified in the transepidermal elimination group. The association of transepidermal elimination with interface changes and a higher parasitic index, without an increased ulceration rate, may reflect a unique biologic alteration in the epidermis, serving to facilitate the extrusion of the parasites through the skin.

Malaria transmission in non-endemic areas: case report, review of the literature and implications for public health management

In non-endemic areas, malaria is rare and locally acquired infections, particularly with Plasmodium falciparum, are exceptional events. The diagnosis is, therefore, likely to be delayed or missed in patients without a relevant travel history. This report describes a case of falciparum malaria in Berlin, Germany, in a patient who had not been to an endemic area for more than a decade. Potential routes of vector-related and direct transmission were evaluated, particularly with regard to a possible danger to the public. A review of the literature was conducted regarding possible routes of transmission and their probability assessed. Genotyping of parasite isolates of this and another patient with malaria admitted 16 days before revealed homology between the two strains. In a local entomological survey, anopheline vectors on the hospital grounds as well as in the residential area of both patients were found. Despite intensive investigations, the mode of transmission remained obscure. In this context, possible routes of vector-borne and direct occupational/accidental transmission in a major European city are reviewed and discussed, providing information and guidance in case other similar events occur elsewhere. Examples for investigations and measures to be taken in such a situation are provided. When local malaria transmission within a large non-immune population cannot be ruled out, genotyping of parasite isolates, local entomological surveys, preparedness for secondary cases, expert consultations in a multidisciplinary team and careful information management are essential. Malaria acquired in non-endemic areas remains an unlikely, but possible event for which awareness needs to be maintained.

Infection risks following accidental exposure to blood or body fluids in health care workers: a review of pathogens transmitted in published cases

Hospital staff and all other human or veterinary health care workers, including laboratory, research, emergency service, or cleaning personnel are exposed to the risk of occupational infection following accidental exposure to blood or body fluids (BBF) contaminated with a virus, a bacteria, a parasite, or a yeast. The human immunodeficiency virus (HIV) or those of hepatitis B (HBV) or C (HCV) account for most of this risk in France and worldwide. Many other pathogens, however, have been responsible for occupational infections in health care workers following exposure to BBF, some with unfavorable prognosis. In developed countries, a growing number of workers are referred to clinicians responsible for the evaluation of occupational infection risks following accidental exposure. Although their principal task remains the evaluation of the risks of HIV, HBV, or HCV transmission and the possible usefulness of postexposure prophylaxis, these experts are also responsible for evaluating risks of occupational infection with other emergent or more rare pathogens and their possible timely prevention. The determinants of the risks of infection and the characteristics of described cases are discussed in this article.

Some aspects of protozoan infections in immunocompromised patients- a review

Protozoa are among the most important pathogens that can cause infections in immunocompromised hosts. These microorganisms particularly infect individuals with impaired cellular immunity, such as those with hematological neoplasias, renal or heart transplant patients, patients using high doses of corticosteroids, and patients with acquired immunodeficiency syndrome. The protozoa that most frequently cause disease in immunocompromised patients are Toxoplasma gondii, Trypanosoma cruzi, different Leishmania species, and Cryptosporidium parvum; the first two species cause severe acute meningoencephalitis and acute myocarditis, Leishmania sp. causes mucocutaneous or visceral disease, and Cryptosporidium can lead to chronic diarrhea with hepatobiliary involvement. Various serological, parasitological, histological and molecular methods for the diagnosis of these infections are currently available and early institution of specific therapy for each of these organisms is a basic measure to reduce the morbidity and mortality associated with these infections.

Laboratory-acquired parasitic infections from accidental exposures

Parasitic diseases are receiving increasing attention in developed countries in part because of their importance in travelers, immigrants, and immunocompromised persons. The main purpose of this review is to educate laboratorians, the primary readership, and health care workers, the secondary readership, about the potential hazards of handling specimens that contain viable parasites and about the diseases that can result. This is accomplished partly through discussion of the occupationally acquired cases of parasitic infections that have been reported, focusing for each case on the type of accident that resulted in infection, the length of the incubation period, the clinical manifestations that developed, and the means by which infection was detected. The article focuses on the cases of infection with the protozoa that cause leishmaniasis, malaria, toxoplasmosis, Chagas' disease (American trypanosomiasis), and African trypanosomiasis. Data about 164 such cases are discussed, as are data about cases caused by intestinal protozoa and by helminths. Of the 105 case-patients infected with blood and tissue protozoa who either recalled an accident or for whom the likely route of transmission could be presumed, 47 (44.8%) had percutaneous exposure via a contaminated needle or other sharp object. Some accidents were directly linked to poor laboratory practices (e.g., recapping a needle or working barehanded). To decrease the likelihood of accidental exposures, persons who could be exposed to pathogenic parasites must be thoroughly instructed in safety precautions before they begin to work and through ongoing training programs. Protocols should be provided for handling specimens that could contain viable organisms, using protective clothing and equipment, dealing with spills of infectious organisms, and responding to accidents. Special care should be exercised when using needles and other sharp objects.

American trypanosomiasis (Chagas' disease)

Gastrointestinal dysfunction is a major problem for many patients with chronic Chagas' disease, as are cardiac dysrhythmias and cardiomyopathy. The underlying anatomic abnormality in these patients is a denervation of the gastrointestinal tract. This process of nerve destruction usually develops insidiously over many years, and it is highly variable in terms of its extent in individual patients as well as in the segments of the gastrointestinal tract that are most affected. Megaesophagus is the most common manifestation of gastrointestinal Chagas disease, and mechanical dilation of the esophageal sphincter or surgery in advanced cases usually give satisfactory relief of symptoms. Megacolon, particularly of the sigmoid segment, is also common in patients with chronic T. cruzi infections, and its presence can be complicated by fecal impaction or sigmoid volvulus. Patients with advanced megacolon who have resections of the sigmoid colon and most of the rectum generally do well postoperatively.

Laboratory-associated infections and biosafety

An estimated 500,000 laboratory workers in the United States are at risk of exposure to infectious agents that cause disease ranging from inapparent to life-threatening infections, but the precise risk to a given worker unknown. The emergence of human immunodeficiency virus and hantavirus, the continuing problem of hepatitis B virus, and the reemergence of Mycobacterium tuberculosis have renewed interest in biosafety for the employees of laboratories and health care facilities. This review examines the history, the causes, and the methods for prevention of laboratory-associated infections. The initial step in a biosafety program is the assessment of risk to the employee. Risk assessment guidelines include the pathogenicity of the infectious agent, the method of transmission, worker-related risk factors, the source and route of infection, and the design of the laboratory facility. Strategies for the prevention and management of laboratory-associated infections are based on the containment of the infectious agent by physical separation from the laboratory worker and the environment, employee education about the occupational risks, and availability of an employee health program. Adherence to the biosafety guidelines mandated or proposed by various governmental and accrediting agencies reduces the risk of an occupational exposure to infectious agents handled in the workplace.