Role of diamine oxidase in the pathogenesis of chronic urticaria

Chronic urticaria is a polyetiological disease proceeding by various immunological and non-immunological (pseudo-allergic) mechanisms. Food intolerance is a distinct type of pseudo-allergies, manifesting, e.g., with histamine intolerance syndrome, caused by imbalance between the histamine accumulation and the ability to degrade it. The purpose of this article was to summarize results of recent studies, to discuss the difficulties of diagnosing this pathology, which primarily depends on the degree of impaired histamine degradation under the influence of diamine oxidase. Diamine oxidase is the main enzyme required for histamine destruction in the intestines, being synthesized by apical enterocytes. The review draws attention to the reasons leading to increased level of histamine not only with consumed food, given its different concentration in the same food products, depending, for example, on their processing and storage, but also with suppressing activity of the enzymes required for metabolism of histamine by various food additives, by the influence of microbiota. The results of studies in which the levels of histamine and/or diamine oxidase activity were determined, which depend on adherence to the diet confirming the association of diamine oxidase with the symptoms of histamine intolerance. According to most studies, the compliance with diet led to increased level of diamine oxidase. However, in some studies, no changes in the activity of this enzyme were found. There are several studies that have evaluated the levels of diamine oxidase in patients with true allergies. Moreover, some authors, in addition to adherence to the diet, evaluated the effectiveness of drugs containing diamine oxidase in patients with low levels of this enzyme in blood serum. The workers also confirm high proportion of histamine intolerance syndrome among various food reactions, suggesting a need for differential diagnosis with other non-immune reactions, including disorders of gastrointestinal tract and psychosomatic reactions. Thus, all the authors confirm the need for laboratory diagnosis of histamine intolerance syndrome, since this will not only increase the efficiency of dietary adherence, but also substantiate the usage of drugs containing diamine oxidase, which will improve quality of life in these cohorts. However, these patients are still treated with low-histamine diets. The literature data confirm the opportunity of using this histamine degradation enzyme as a biological marker of histamine intolerance syndrome, and recommend its assays for inclusion into the diagnostic algorithm for chronic urticaria

Detection of tick-borne pathogens in wild birds and their ticks in Western Siberia and high level of their mismatch

Abstract: The Tomsk region located in the south of Western Siberia is one of the most high-risk areas for tick-borne diseases due to elevated incidence of tick-borne encephalitis and Lyme disease in humans. Wild birds may be considered as one of the reservoirs for tick-borne pathogens and hosts for infected ticks. A high mobility of wild birds leads to unpredictable possibilities for the dissemination of tick-borne pathogens into new geographical regions. The primary goal of this study was to evaluate the prevalence of tick-borne pathogens in wild birds and ticks that feed on them as well as to determine the role of different species of birds in maintaining the tickborne infectious foci. We analysed the samples of 443 wild birds (60 species) and 378 ticks belonging to the genus Ixodes Latraille, 1795 collected from the wild birds, for detecting occurrence of eight tick-borne pathogens, the namely tick-borne encephalitis virus (TBEV), West Nile virus (WNV), and species of Borrelia, Rickettsia, Ehrlichia, Anaplasma, Bartonella and Babesia Starcovici, 1893, using RT-PCR/or PCR and enzyme immunoassay. One or more tick-borne infection markers were detected in 43 species of birds. All markers were detected in samples collected from fieldfare Turdus pilaris Linnaeus, Blyth’s reed warbler Acrocephalus dumetorum Blyth, common redstart Phoenicurus phoenicurus (Linnaeus), and common chaffinch Fringilla coelebs Linnaeus. Although all pathogens have been identified in birds and ticks, we found that in the majority of cases (75.5%), there were mismatches of pathogens in birds and ticks collected from them. Wild birds and their ticks may play an extremely important role in the dissemination of tick-borne pathogens into different geographical regions

Обнаружение и генотипирование Anaplasma phagocytophilum в клещах I. persulcatus и D. reticulatus , собранных в г. Томске в 2015–2016 гг.

Introduction. The detection of the first cases of tick-borne human granulocytic anaplasmosis in Russia, discovery of genetic markers for Anaplasma spp. in ixodid ticks and reporting of a significant number of cases of tick-borne infections in the southern part of Western Siberia give reason to suppose that causative agents of tick-borne anaplasmosis may be transmitted in Tomsk and its suburbs. Objective. To study the distribution and species biodiversity of A. phagocytophilum in ixodid ticks in Tomsk Region. Materials and methods. The analysis of 690 individual ixodid ticks (larvae and adults) was carried out for Ixodes persulcatus (n = 530) and Dermacentor reticulatus (n = 160) ticks collected in 2015–2016 on the territory of urban and suburban biotopes of Tomsk. Primary screening of ticks for the presence of genetic material of A. phagocytophilum was conducted using two-round PCR with species-specific primers for the 16S rRNA gene. The amplification (1,220 kB) of the groESL fragment of the heat shock protein operon was performed for positive isolates with subsequent determination of the nucleotide sequence in the gene fragment for phylogenetic analysis. Results. The number of A. phagocytophilum positive samples for I. persulcatus (larvae) was 1.2 ± 0.6%, I. persulcatus (adult) was 1.8 ± 0.7%; and D. reticulatus (adult) was 0.6 ± 0.3%. Analysis of the nucleotide sequence of the gene fragments in groESL operon for nine isolates confirmed that the genetic material of the granulocytic anaplasmosis was detected. Phylogenetic analysis showed that all the isolates belonged to the first group of the “new cluster” of A. phagocytophilum. Conclusion. The causative agent of human granulocytic anaplasmosis has been newly detected in I. persulcatus ticks collected in urban and suburban biotopes of Tomsk and in D. reticulatus from urban foci.Введение. Выявление первых случаев заболевания клещевым гранулоцитарным анаплазмозом человека в Российской Федерации, обнаружение генетических маркеров анаплазмозов в иксодовых клещах, регистрация значительного количества случаев различных клещевых инфекций на юге Западной Сибири ставят вопрос о возможной циркуляции возбудителя анаплазмоза в г. Томске и его пригородах. Цель исследования. Изучение распространения и видового разнообразия A. phagocytophilum в иксодовых клещах на территории Томской области. Материалы и методы. Проведен анализ 690 индивидуальных образцов личинок и имаго иксодовых клещей видов Ixodes persulcatus (n = 530) и Dermacentor reticulatus (n = 160), собранных в 2015–2016 гг. на территории городских и пригородных биотопов г. Томска. Первичный скрининг клещей на наличие генетического материала A. phagocytophilum проводили с помощью двухраундовой полимеразной цепной реакции в присутствии родоспецифичных праймеров из области гена 16S рРНК. Для положительных изолятов осуществлялось амплифицирование фрагмента (1 220 пар нуклеотидов) groESL-оперона белков теплового шока с последующим определением нуклеотидной последовательности фрагмента гена и проведением филогенетического анализа. Результаты. Уровень инфицированности A. phagocytophilum у личинок I. persulcatus составил (1,2 ± 0,6)%; у половозрелых особей I. persulcatus – (1,8 ± 0,7)%; у половозрелых особей D. reticulatus–(0,6 ± 0,3)%. Анализ нуклеотидной последовательности фрагмента groESL-оперона для девяти изолятов подтвердил обнаружение генетического материала возбудителя гранулоцитарного анаплазмоза. Филогенетический анализ показал, что все изоляты относятся к первой группе «нового» кластера A. phagocytophilum. Вывод. Возбудитель гранулоцитарного анаплазмоза человека впервые обнаружен в клещах I. рersulcatus, собранных в городских и пригородных биотопах г. Томска, и D. reticulatus из городского биотопа

Detection and genotyping of Anaplasma phagocytophilum in I. persulcatus and D. reticulatus ticks collected in Tomsk (Western Siberia) in 2015–2016

Introduction. The detection of the first cases of tick-borne human granulocytic anaplasmosis in Russia, discovery of genetic markers for Anaplasma spp. in ixodid ticks and reporting of a significant number of cases of tick-borne infections in the southern part of Western Siberia give reason to suppose that causative agents of tick-borne anaplasmosis may be transmitted in Tomsk and its suburbs. Objective. To study the distribution and species biodiversity of A. phagocytophilum in ixodid ticks in Tomsk Region. Materials and methods. The analysis of 690 individual ixodid ticks (larvae and adults) was carried out for Ixodes persulcatus (n = 530) and Dermacentor reticulatus (n = 160) ticks collected in 2015–2016 on the territory of urban and suburban biotopes of Tomsk. Primary screening of ticks for the presence of genetic material of A. phagocytophilum was conducted using two-round PCR with species-specific primers for the 16S rRNA gene. The amplification (1,220 kB) of the groESL fragment of the heat shock protein operon was performed for positive isolates with subsequent determination of the nucleotide sequence in the gene fragment for phylogenetic analysis. Results. The number of A. phagocytophilum positive samples for I. persulcatus (larvae) was 1.2 ± 0.6%, I. persulcatus (adult) was 1.8 ± 0.7%; and D. reticulatus (adult) was 0.6 ± 0.3%. Analysis of the nucleotide sequence of the gene fragments in groESL operon for nine isolates confirmed that the genetic material of the granulocytic anaplasmosis was detected. Phylogenetic analysis showed that all the isolates belonged to the first group of the “new cluster” of A. phagocytophilum. Conclusion. The causative agent of human granulocytic anaplasmosis has been newly detected in I. persulcatus ticks collected in urban and suburban biotopes of Tomsk and in D. reticulatus from urban foci

Detection of <i>Ehrlichia</i> spp. and <i>Theileria</i> spp. in <i>Hyalomma anatolicum</i> ticks collected in Tajikistan

The objectives of our study were to survey the prevalence of genetic markers for Rickettsia spp., Ehrlichia spp., Anaplasma spp., Babesia spp., and Theileria spp. in Hyalomma anatolicum ticks collected in southwestern Tajikistan and to perform sequencing and phylogenetic analysis of fragments of the 16S rRNA gene and groESL ope-ron from Ehrlichia spp. and fragments of the 18S rRNA gene of Theileria spp. detected in H. anatolicum ticks. Hyalomma anatolicum ticks collected in the Tursunzade and Rudaki districts of Tajikistan were tested for DNA of Rickettsia spp., Ehrlichia spp., Anaplasma spp., Babesia spp., and Theileria spp. by PCR with specific primers. The amplified fragments were sequenced and analyzed. DNA of Ehrlichia spp. (3.3 %) and Theileria spp. (3.3 %) was detected only in H. anatolicum ticks collected from the Rudaki district, and DNA of Ehrlichia spp. (0.7 %) was found in H. anatolicum ticks from the Tursunzade district. Sequence analysis of fragments of the 16S rRNA gene and groESL operon from Ehrlichia spp. revealed high similarity to Ehrlichia spp. The Tajik isolates of Theileria spp. were genotyped as Theileriaannulata based on the analysis of 18S rRNA gene sequences. The phylogenetic analysis demonstrates that Ehrlichia spp. isolates are highly similar to Ehrlichia spp. circulating in China and Brazil. The isolate Tajikistan-5 is closely related to the putative novel species Ehrlichia mineirensis. The Tajik isolates of Theileria spp. were clustered with T. annulata isolates from Turkey, Iran, Pakistan, and China by phylogenetic analyses

The Viromes of Mosquitoes from the Natural Landscapes of Western Siberia

The metagenomic analysis of mosquitoes allows for the genetic characterization of mosquito-associated viruses in different regions of the world. This study applied a metagenomic approach to identify novel viral sequences in seven species of mosquitoes collected from the Novosibirsk region of western Siberia. Using NGS sequencing, we identified 15 coding-complete viral polyproteins (genomes) and 15 viral-like partial sequences in mosquitoes. The complete sequences for novel viruses or the partial sequences of capsid proteins, hypothetical viral proteins, and RdRps were used to identify their taxonomy. The novel viral sequences were classified within the orders Tymovirales and Picornavirales and the families Partitiviridae, Totiviridae, Tombusviridae, Iflaviridae, Nodaviridae, Permutotetraviridae, and Solemoviridae, with several attributed to four unclassified RNA viruses. Interestingly, the novel putative viruses and viral sequences were mainly associated with the mosquito Coquillettidia richardii. This study aimed to increase our understanding of the viral diversity in mosquitoes found in the natural habitats of Siberia, which is characterized by very long, snowy, and cold winters