Associating Land Cover Changes with Patterns of Incidences of Climate-Sensitive Infections: An Example on Tick-Borne Diseases in the Nordic Area.

Some of the climate-sensitive infections (CSIs) affecting humans are zoonotic vector-borne diseases, such as Lyme borreliosis (BOR) and tick-borne encephalitis (TBE), mostly linked to various species of ticks as vectors. Due to climate change, the geographical distribution of tick species, their hosts, and the prevalence of pathogens are likely to change. A recent increase in human incidences of these CSIs in the Nordic regions might indicate an expansion of the range of ticks and hosts, with vegetation changes acting as potential predictors linked to habitat suitability. In this paper, we study districts in Fennoscandia and Russia where incidences of BOR and TBE have steadily increased over the 1995-2015 period (defined as 'Well Increasing districts'). This selection is taken as a proxy for increasing the prevalence of tick-borne pathogens due to increased habitat suitability for ticks and hosts, thus simplifying the multiple factors that explain incidence variations. This approach allows vegetation types and strengths of correlation specific to the WI districts to be differentiated and compared with associations found over all districts. Land cover types and their changes found to be associated with increasing human disease incidence are described, indicating zones with potential future higher risk of these diseases. Combining vegetation cover and climate variables in regression models shows the interplay of biotic and abiotic factors linked to CSI incidences and identifies some differences between BOR and TBE. Regression model projections up until 2070 under different climate scenarios depict possible CSI progressions within the studied area and are consistent with the observed changes over the past 20 years.

Study of the Relationship between the Average Annual Temperature of Atmospheric Air and the Number of Tick-Bitten Humans in the North of European Russia.

In recent decades, a considerable increase in the number of tick-bitten humans has been recorded in the north of European Russia. At the same time, significant climatic changes, such as an increase in air temperature, were noticed in this region. The northern border of the ixodidae distribution area lies in the north of European Russia, therefore the analysis of the population dynamics is of particular interest regarding the possible impact of the climate changes. Unfortunately, in such a large territory field, studies on tick abundance are very difficult. In our study, the official statistics for the number of tick-bitten humans were used. This kind of statistical analysis has been conducted in the Russian Federation for many years, and can be used for the estimation of climate change impact on tick abundance. Statistical data on tick-bitten humans have been collected in three large regions for several decades. For the same regions, the average annual air temperature was calculated and modeled. An S-shaped distribution of the number of victims depending on the average annual air temperature was established, which can be described as "Verhulst's law", or logistic function. However, the development of the population does not depend on time, but on the temperature of the ambient air.

Migratory birds along the Mediterranean - Black Sea Flyway as carriers of zoonotic pathogens.

At the crossroad between Europe, Asia, and Africa, Bulgaria is part of the Mediterranean - Black Sea Flyway (MBSF) used by millions of migratory birds. In this study, bird species migrating through Bulgaria were investigated as carriers of zoonotic pathogens. In total, 706 birds belonging to 46 species were checked for the presence of various bacterial pathogens (Campylobacter, Yersinia, Salmonella, Listeria, Escherichia coli, Staphylococcus aureus, Francisella tularensis, Coxiella burnetii, Borrelia burgdorferi, and Brucella spp.). From 673 birds we investigated fecal samples, from the remaining 33, blood samples. We detected Campylobacter 16S rDNA gene in 1.3% of birds, but none were of pathogenic Campylobacter jejuni and Campylobacter coli species. Escherichia coli 16S rDNA gene was found in 8.8% of the birds. Out of 34 birds that transported Yersinia enterocolitica strains (5.05%), only 1 carried a pathogenic isolate. Three birds (0.4%) were carriers of nonpathogenic Salmonella strains. Four avian samples (0.6%) were positive for Listeria monocytogenes and 1 (0.15%) was positive for Brucella spp. None of the birds tested carried the tick-borne pathogens C. burnetii or B. burgdorferi sensu lato. Antibiotic-resistant strains were detected, suggesting that migratory birds could be reservoirs and spreaders of bacterial pathogens as well as antibiotic resistance genes.

Draft Genome Sequence of Coxiella burnetii Historical Strain Leningrad-2, Isolated from Blood of a Patient with Acute Q Fever in Saint Petersburg, Russia.

This is the announcement of a draft genome sequence of Coxiella burnetii strain Leningrad-2, phase I. The strain, which is mildly virulent in infected guinea pigs, was isolated in 1957 from the blood of a patient with acute Q fever in Leningrad (now Saint Petersburg), Russia.

Molecular Markers of Pesticide Resistance and Pathogens in Human Head Lice (Phthiraptera: Pediculidae) From Rural Georgia, USA.

Although the head louse, Pediculus humanus capitis De Geer, and body louse, Pediculus humanus humanus L., both have a worldwide distribution, the occurrence of head louse pediculosis appears to be more prevalent in modern societies despite systematic use of various pediculicides. This study tested head lice collected in rural Georgia and body lice collected in Russia for the prevalence of a kdr-biomarker that is associated with permethrin resistance. This study also screened lice for the presence of DNA from Bartonella quintana and Acinetobacter species. The kdr-permethrin resistance biomarker for the T917I mutation was detected by RFLP and PCR in 99.9% of head lice tested from Georgia, whereas only 2.9% of body lice from Russia tested positive for this kdr biomarker. DNA of B. quintana was detected in 10.3% of head lice from Georgia, whereas 84.8% of body lice from Russia tested positive. Acinetobacter DNA was detected in 80.8% (95% CI, 68-89%) of head lice from Georgia and all body lice from Russia tested.

The impact of climate change on the expansion of Ixodes persulcatus habitat and the incidence of tick-borne encephalitis in the north of European Russia.

BACKGROUND: The increase in tick-borne encephalitis (TBE) incidence is observed in recent decades in a number of subarctic countries. The reasons of it are widely discussed in scientific publications. The objective of this study was to understand if the climate change in Arkhangelsk Oblast (AO) situated in the north of European subarctic zone of Russia has real impact on the northward expansion of Ixodid ticks and stipulates the increase in TBE incidence. METHODS: This study analyzes: TBE incidence in AO and throughout Russia, the results of Ixodid ticks collecting in a number of sites in AO, and TBE virus prevalence in those ticks, the data on tick bite incidence in AO, and meteorological data on AO mean annual air temperatures and precipitations. RESULTS: It is established that in recent years TBE incidence in AO tended to increase contrary to its apparent decrease nationwide. In last 10 years, there was nearly 50-fold rise in TBE incidence in AO when compared with 1980-1989. Probably, the increase both in mean annual air temperatures and temperatures during tick active season resulted in the northward expansion of Ixodes Persulcatus, main TBE virus vector. The Ixodid ticks expansion is confirmed both by the results of ticks flagging from the surface vegetation and by the tick bite incidence in the population of AO locations earlier free from ticks. Our mathematical (correlation and regression) analysis of available data revealed a distinct correlation between TBE incidence and the growth of mean annual air temperatures in AO in 1990-2009. CONCLUSION: Not ruling out other factors, we conclude that climate change contributed much to the TBE incidence increase in AO.

Detection and identification of bacterial agents in Ixodes persulcatus Schulze ticks from the north western region of Russia.

Ixodes persulcatus Schultze ticks are traditionally associated with transmission of Lyme disease, babesiosis, and tick-borne encephalitis. Here we compared the prevalence of infection with Borrelia burgdorferi, and rickettsial and ehrlichial agents in I. persulcatus ticks collected in different locations of the North Western administrative region of Russia. Altogether, 27.7% of ticks were infected with at least one organism, while the DNA of two or more bacteria was found in 11.8% of ticks tested. The highest average prevalence of Anaplasmataceae (20.8%) was detected in ticks from Arkhangel'sk province, while the prevalence in ticks from Novgorod province and St. Petersburg, respectively, was 7.3% and 12.2%. Only Ehrlichia muris DNA was identified by DNA sequencing. In comparison, the prevalence of B. burdorferi DNA was 16.6%, 5.8%, and 24.5% in the respective locations. The 382-bp amplicon of gltA from Candidatus Rickettsia tarasevichiae was detected in 2.75% and 1.6%, respectively, of ticks from Arkhangel'sk and Novgorod provinces, extending further west and north the area where this rickettsia is known to be present. DNA of the rickettsia-like endosymbiont Montezuma was primarily associated with female ticks, 8-28% of which were infected. Since I. persulcatus is so commonly infected with multiple agents that may cause human diseases, exposure to these ticks poses significant risk to human health in this region.

Prevalence of bacterial agents in Ixodes persulcatus ticks from the Vologda Province of Russia.

The prevalence of rickettsiae, ehrlichiae, and the rickettsia-like endosymbiont called Montezuma relative to that of Borrelia was determined in questing Ixodes persulcatus (I. persulcatus) ticks collected in 2002-2003 from Vologda Province, Russia. Ehrlichia muris, Anaplasma phagocytophilum, Montezuma, and new spotted fever group rickettsiae were detected by polymerase chain reaction (PCR) for the first time in this area. The rickettsiae were all Candidatus Rickettsia tarasevichiae, the furthest west this organism has been detected. After Borrelia, Montezuma was the agent most frequently detected; it may be present throughout the distribution of I. persulcatus in Russia. Ehrlichiae and rickettsiae frequently share the same tick host with Borrelia burgdorferi sensu lato so cotransmission and mixed infections in vertebrate hosts, including humans, may occur.