Vol 26, No 4 (2021)

Brucellosis is an infectious particularly dangerous zoonotic disease caused by bacteria of the genus Brucella, among which B. melitensis, B. abortus, and B. suis have pathogenic potential, causing a severe and often chronic course of the disease.

Laboratory diagnostics is crucial for the detection of human cases, since the clinical symptoms of human brucellosis are variable and nonspecific. Laboratory diagnosis of brucellosis is based on three different approaches: direct bacteriological method, indirect method using serological and allergic tests and direct express method in different formats of molecular polymerase chain reaction.

Despite the accumulated experience of using serological tests and the highly sensitive polymerase chain reaction method, the isolation of Brucella culture is considered the gold standard in the laboratory diagnosis of brucellosis due to its clinical and epidemiological relevance. The currently available automated systems of the bacteriological method have increased its sensitivity and shortened the detection time of Brucella species.

The main limitations of serological tests are the lack of general interpretation criteria, low specificity due to cross-reactions with other bacteria and low sensitivity at an early stage of the disease. At the same time, in Russia, serological tests account for more than 99% of all laboratory tests and remain the main diagnostic tool. This is due to their inexpensive and convenient use at the place of medical care in endemic areas and high negative prognostic value.

Polymerase chain reaction in various formats of rapid tests diagnoses the DNA of the pathogen in a few hours with high sensitivity and specificity. Nevertheless, a positive polymerase chain reaction result requires careful interpretation and does not necessarily indicate an active infection.

For the convenience of using diagnostic approaches to brucellosis in practical medicine and determining the activity of the infectious process, it is necessary to improve diagnostics and develop express methods.

The review shows both the most routine and modern laboratory methods currently available for laboratory diagnosis of brucellosis.

BACKGROUND: Monkeypox, a zoonotic disease caused by an orthopoxvirus, results in a smallpox-like or a chickenpox-like disease. Monkeypox in human was first diagnosed in 1970 in the Democratic Republic of the Congo and subsequently has spread to other regions of Africa (primarily West and Central). In 2003 the first monkeypox outbreak occurred outside of Africa in USA. The latest outbreak of monkeypox in May 2022 is characterized by the simultaneous involvement of several hundred people. The appearance of cases outside of Africa highlights the risk for geographical spread and the global relevance of the disease requiring the epidemiologic studies and the search for effective methods of prevention and therapy.

AIMS: To summarize and systematize the results of studies on the epidemiology, diagnosis, clinical picture, the role of vaccination and treatment of monkeypox, including taking into account the last outbreak of the disease in May 2022 in non-endemic regions.

MATERIALS AND METHODS: A systematic literature search was conducted in MEDLINE (Ovid), MEDLINE (PubMed), and the Google Scholar database published up to May 31, 2022, using the keywords "monkeypox" or "monkeypox virus" or "smallpox human monkeys". We primary selected 112 abstracts. After removing duplicates and irrelevant articles, 48 full-text articles have been selected. After reviewing the full-text article versions, 15 articles were excluded due to highly specialized biological topics, poor study design, quality of results, or their unavailability. Ultimately, this review included 33 articles, in addition to which 6 founding and supporting websites were cited.

RESULTS: Monkeypox cases among humans have been on the rise since the 1970s, primarily in endemic areas. The median age at the time of treatment increased from 4 (1970s) to 21 (2010–2019). Since 2003, the spread of monkeypox outside Africa has been noted, associated with the importation of infected animals, migration and tourism. Transmission to humans occurs through close contact with an infected animal (70%), a person or material contaminated with the virus. Monkeypox presents with fever, vesicular rash, and lymphadenopathy lasting 2 to 4 weeks. Mortality is associated with the development of complications and is 10.6% for the Central African clade compared to 3.6% for the West African clade. There have been no deaths outside of Africa. Our review shows an escalation of monkeypox cases, especially in endemic Africa and spread to other countries, which is likely due to the discontinuation of smallpox vaccination, which provided cross-protection against monkeypox. Unfortunately, smallpox vaccination is contraindicated in immunocompromised individuals, despite the availability of recommended vaccines. The effectiveness of existing antiviral drugs (tecovirimate and brincidofovir) has been little studied in humans.

CONCLUSION: The weakening of population immunity, associated with the cessation of vaccination against smallpox, created the prerequisites for the outbreaks of monkeypox, including in non-endemic areas. Surveillance and detection programs are important tools for understanding the ever-changing epidemiology of this disease. In light of the emergence of cases outside of Africa, the potential for human-to-human transmission of the virus, the public health significance of monkeypox should not be underestimated.

BACKGROUND: The epidemiological situation with measles remains unstable, with periodic increases in morbidity. In the Russian Federation, as well as in other countries, cases of nosocomial infection continue to be registered. Medical workers may be involved in the epidemic process and serve, among other things, as a source of infection for patients.

AIMS: assessment of postvaccinal immunity to measles in medical workers in Kazan during its elimination period.

MATERIALS AND METHODS: A cross-sectional study of immunity to measles was conducted in 515 employees of medical institutions in Kazan. 376 medical staff had documented ever-evidence of immunization against measles. Measles class G immunoglobulin levels were determined, specific immunity strength was assessed as a function of age, and time since the last vaccine dose was administered. Relative values (fractions, %) and standard error of the fraction (%) were calculated. A correlation analysis was performed.

RESULTS: The proportion of seropositive medical workers was 81% (95% CI 79.3–82.7) of all those examined. Those over 50 years of age were the most protected: antibodies were detected in 90.3% (95% CI 85.96–94.64) of them. Among the 417 persons with antibodies low level was detected in 60.9% (95% CI 56.12–65.68), medium level ― in 34.5% (95% CI 29.84–39.16), high level ― only in 4.6% (95% CI 2.54–6.66) of the examined persons. In all age groups, the share of persons with low levels of protective antibodies was the highest. High level of protective antibodies was registered only in the age groups 40–49 years and 50 years and older ― 4.8% (95% CI 0.98–8.62) and 7% (95% CI 3.26–10.74), respectively. Antibody levels correlated inversely with time since vaccination (p <0.05).

CONCLUSIONS: The results of serologic study of health workers demonstrate insufficient protection of health workers against measles, especially in younger groups. Decreased immunity in vaccinated health workers 10 or more years after immunization necessitates the monitoring of antibody levels in this group and consideration of revaccination.

The spread of COVID-19 over the past three years has posed difficult tasks for doctors related to rapid diagnosis and provision of highly qualified medical care to patients, including with co-infection ― SARS-CoV-2/human immunodeficiency virus.

The analysis of the combined course of COVID-19 and human immunodeficiency virus demonstrated the synergistic effect of SARS-CoV-2 and human immunodeficiency virus on the human body. Numerous studies have shown that COVID-19 is more severe and is accompanied by high mortality in older people and in the presence of comorbid pathology. Including important role belongs to diseases accompanied by suppression of cellular immunity, which lead to frequent complications and longer viremia, which can be observed with human immunodeficiency virus infection. The similarity of clinical, laboratory and radiological data does not allow to differentiate COVID-19 and human immunodeficiency virus opportunistic diseases with lung damage (pneumocystic pneumonia, cytomegalovirus and candidiasis etiology), in an early period, especially in patients without an established human immunodeficiency virus status.

Identification of the features of the course of the disease, alertness towards human immunodeficiency virus infection in patients admitted to the hospital with COVID-19 at a young age, the peculiarities of the epidemiological history will allow early diagnosis and improve management tactics.