Study on the Prevalence of Pneumocystis jirovecii as a Causative Agent of Lung Pathology in People with Different Immune Status.

BACKGROUND: Pneumocystis pneumonia (PCP) commonly affects immunocompromised individuals, whereas in immunocompetent persons, it occurs relatively rarely, and in most cases, the Pneumocystis infection is detected as an asymptomatic colonization. The present study aimed to establish the prevalence of Pneumocystis jirovecii infection in human hosts with different immune status (immunocompromised and immunocompetent), using molecular diagnostic methods, and to compare their diagnostic value with that of classical staining methods. METHODS: We used the collected-to-this-moment data from a prospective study on the prevalence of pneumocystosis among the Bulgarian population. Clinical specimens (including throat secretions, induced sputum, tracheal aspirates, and bronchoalveolar lavage) collected from 220 patients suspected of PCP (153 immunocompetent and 67 immunocompromised patients) were examined with microscopic staining methods and real-time PCR for detection of P. jirovecii. Results: DNA of the pathogen was detected in 38 (17%) specimens (32 immunocompromised patients and 6 immunocompetent subjects). From all 220 clinical samples examined by staining methods, only five (2%) P. jirovecii cysts were detected by the Gomori stain. All patients with PCP were treated with trimethoprim-sulfamethoxazole, but in ten of them (HIV-positive patients), the disease had a fatal outcome. CONCLUSIONS: This study is the first in Bulgaria including the main available laboratory methods for diagnosis of human pneumocystosis. Regarding the etiological diagnosis of PCP, in our study the sensitivity of real-time PCR was higher compared to the staining methods. The choice of a method for sample collection and examination has an important role in the efficiency of the laboratory diagnostics.

Epidemiological and clinical characteristics of imported malaria in Bulgaria: A retrospective study of а 21-year period.

BACKGROUND: Bulgaria, with a high endemicity for malaria in the past, was declared by the WHO as a malaria-free country in 1965. We intended to analyze the epidemiological and clinical implications of imported malaria cases in Bulgaria. METHODS: This is a retrospective cross-sectional analysis of all recorded cases of imported malaria in Bulgaria over a 21-year period (2000-2020). Patients' clinical records and information gathered from the epidemiological survey of each recorded malaria case were reviewed. RESULTS: A total of 232 cases of imported malaria were reported, 147 (63.4%) were Bulgarian citizens (BC) and 85 (36.6%) were foreign nationals (FN). Two thirds (66.4%) of cases were diagnosed from April to October. Most BCs had travelled for work (66.6%) to Africa (93.9%) and were infected with P. falciparum (83.3%), while most FNs were migrants (54.7%), exposed in Asia (63.5%) with P. vivax infection (62.4%). Clinical complications and a fatal outcome were noted in 14.7% (n = 34) and 3.5% (n = 8) of cases respectively. All complicated cases were in BNs with P. falciparum infection. CONCLUSIONS: Bulgaria experiences a steady import of malaria. Efforts to improve diagnosis, management and prevention of malaria, as well as maintenance of a high degree of epidemiological vigilance are needed.

Study of IgG avidity and the level of specific IgA antibodies and their significance in the diagnosis of human toxocarosis.

Toxocarosis is a zoonotic disease caused by migration and subsequent localization of nematode larvae of Toxocara spp. in human organs and tissues, which is manifested with development of various non-specific clinical symptoms. Main diagnostic methods are serological and consists in proving the presence of anti-Toxocara IgG antibodies in patient's sera. In humans, anti-Toxocara IgG has been shown to persist in the serum for a long time and cannot be used to distinguish between past and recent infection. Aim of the present work is to investigate the diagnostic significance of the specific IgG avidity level, determined by an immuno enzyme test developed by us, and the presence of anti-Toxocara IgA for distinguishing between acute and chronic toxocarosis. The study included 130 patients with positive results in routine serological ELISA and Western blot tests and with clinical symptoms of visceral and ocular toxocarosis. The results revealed low IgG avidity (≤40%) in nine (7.3%) and presence of anti-Toxocara IgA antibodies in 36 (26.2%) of the subjects. Low avidity of IgG antibodies was found only in the first tests, and a presence of specific IgA for up to 9 months. The results of our study give us reason to believe that determination of the IgG avidity in toxocarosis is of greater diagnostic value than the presence of IgA to establish the stage of the disease.

Human Parasitic Diseases in Bulgaria in Between 2013-2014.

BACKGROUND: In Bulgaria, more than 20 autochthonous human parasitic infections have been described and some of them are widespread. Over 50 imported protozoan and helminthic infections represent diagnostic and therapeutic challenges and pose epidemiological risks due to the possibility of local transmission. AIMS: To establish the distribution of autochthonous and imported parasitic diseases among the population of the country over a 2-year period (2013-2014) and to evaluate their significance in the public health system. STUDY DESIGN: Cross sectional study. METHODS: We used the annual reports by regional health inspectorates and data from the National Reference Laboratory at the National Centre of Infectious and Parasitic Diseases on all individuals infected with parasitic diseases in the country. Prevalence was calculated for parasitic diseases with few or absent clinical manifestations (oligosymptomatic or asymptomatic infections). Incidence per 100.000 was calculated for diseases with an overt clinical picture or those that required hospitalisation and specialised medical interventions (e.g. surgery). RESULTS: During the research period, parasitological studies were conducted on 1441.244 persons, and parasitic infections were diagnosed in 22.039 individuals. Distribution of various parasitic pathogens among the population displayed statistically significant differences in prevalence for some intestinal parasites (enterobiasis 0.81%, giardiasis 0.34% and blastocystosis 0.22%). For certain zoonotic diseases such as cystic echinococcosis (average incidence of 3.99 per 100.000) and trichinellosis (average incidence of 0.8 per 100.000), the incidence exceeds several times the annual incidence recorded in the European Union. CONCLUSION: Parasitic diseases still pose a substantial problem with social and medical impacts on the residents of our country. Improved efficiency regarding autochthonous and imported parasitic diseases is essential in providing the public health system the tools it needs to combat these diseases. Attention should be focused on the various imported vector-borne parasitic diseases (e.g. malaria and cutaneous leishmaniasis) for which the country is potentially endemic.