Molecular detection of Francisella tularensis in small ruminants and their ticks in western Iran

Molecular Detection of Francisella spp. in Blood, Milk, and Ticks Infesting Small Ruminants in Urmia, Iran

Background: Zoonotic diseases pose a significant global health challenge, accounting for over half of all newly emerging infectious illnesses. One such pathogenic agent is the bacterium Francisella tularensis, which causes tularemia, a zoonotic disease spread in the Northern Hemisphere through various means, including tick bites. Unfortunately, there is limited literature on tick-borne bacteria affecting human and animal health. This research confirmed the presence of Francisella spp. in ticks in the Urmia region, highlighting the potential for ticks to act as vectors for transmitting the bacteria to livestock and humans. Materials and Methods: A total of 397 ticks, 315 blood samples, and 241 milk samples were gathered from sheep and goats to screen for the existence of Francisella spp. The nested PCR technique revealed the existence of Francisella spp. 16S rRNA gene in the samples. Results: Blood and milk samples from small ruminants did not show the presence of Francisella spp., but the bacteria were detected in 6 tick pools (n = 79; 7.59%; 95% CI: 3.52%-15.59%). The positive ticks identified were Hyalomma asiaticum 2 (n = 24; 8.33%; 95% CI: 2.31%-25.84%), Hyalomma eagyptum 3 (n = 9; 33.33%; 95% CI: 12.06%-64.58%), and Rhipicephalus sanguineus 1 (n = 15; 6.67%; 95% CI: 1.19% - 29.82%) and the presence of Francisella tularensis subspecies holarctica was found to be positive in 3 out of 79 tick pools (3.80%; 95% CI: 1.3 % - 10.58%). The positive ticks identified in this experiment were female Hyalomma aegyptium (1 out of 3; 33.33%; 95% CI: 6.15% - 79.23%), male Hyalomma asiaticum (1 out of 14; 7.14%; 95% CI: 1.27% - 31.47%) and female Rhipicephalus sanguineus (1 out of 7; 14.29%; 95% CI: 2.57% - 51.32%). Conclusion: The study explored the presence of Francisella species, especially the most dangerous, F. tularensis, in small ruminants and the ticks that attach to them using molecular techniques in the Urmia region of northwestern Iran. The research seeks to improve knowledge of Francisella spp. epidemiology. Understanding the risk of human-livestock transmission of this pathogen is crucial for public health, particularly for individuals working in animal-related fields.

Molecular diagnosis of infective endocarditis from culture-negative valve samples in a tertiary hospital in Iran

The aim of this study was to investigate the prevalence of Tropheryma whipplei, Chlamydia psittaci, Chlamydia pneumoniae, Legionella, Brucella, and Francisella tularensis in valve samples from endocarditis patients using the real-time PCR method at a major referral heart hospital in Iran. In this study, 146 paraffin-embedded tissue samples from the heart valves of patients with clinical and pathological evidence of infective endocarditis (IE), who underwent heart valve replacement surgery between 2016 and 2020 at Tehran Heart Center were collected. After DNA extraction from paraffin-embedded valve tissue samples, they were surveyed for the presence of T. whipplei, C. psittaci, C. pneumoniae, Legionella, Brucella, and F. tularensis using quantitative real-time PCR (qPCR). The 16S rRNA gene sequence analysis was used for accurate species identification. Based on the molecular results, T. whipplei, Chlamydia spp., and Legionella spp. were detected in 10 (6.84%), 6 (4.1%), and 3 (2.05%) valve samples, respectively. In addition, one of six positive samples for Chlamydia spp. was identified as C. psittaci. No positive samples for F. tularensis and Brucella were found. In addition, all control valve samples were negative for all investigated pathogens. The findings suggest that specific bacterial species such as T. whipplei, Chlamydia spp., and Legionella spp. are associated with the development of IE. Considering the life-threatening nature of IE, it is critical for healthcare systems to prioritize the identification of its causative agents and develop targeted treatment strategies.IMPORTANCEInfective endocarditis (IE) is a serious and potentially life-threatening condition, and it is associated with significant morbidity, mortality, and complications, making it a major concern in both global and national healthcare systems. Late diagnosis and failure to receive appropriate treatment for patients with culture-negative endocarditis caused by hard-to-grow bacteria can lead to the death of patients. Unfortunately, in Iran, less attention is paid to the role of organisms that are difficult to cultivate in laboratory settings such as Tropheryma whipplei, Chlamydia psittaci, Chlamydia pneumoniae, Legionella, Brucella, and Francisella tularensis in causing culture-negative endocarditis, and these pathogens are overlooked by infectious, cardiologists, and health officials. This study underscores the need for special attention in the diagnosis of the agents of IE.

The Epidemiological Investigation of Yersinia pestis, Francisella tularensis, and Arenavirus Infections in Small Mammals in Northwestern Iran

Background: The control and prevention of rodent-borne diseases are mainly based on our knowledge of ecology and the infectious status of their reservoir hosts. This study aimed to evaluate the prevalence of Francisella tularensis, Yersinia pestis, and arenavirus infections in small mammals and to assess the potential of disease occurrence in East Azerbaijan, northwest of Iran, in 2017 and 2018. Methods: Spleen and lung samples were obtained from all trapped small mammals. The real-time quantitative PCR (qPCR) method was used to detect nucleic acid sequences of F. tularensis, Y. pestis, and arenaviruses. Serum samples were tested for antibodies indicating the host response to F. tularensis and Y. pestis infections using the standard tube agglutination test and enzyme-linked immunosorbent assay (ELISA), respectively. Results: A total of 205 rodents, four Eulipotyphla, and one carnivore were captured. The most common rodent species captured (123 of 205 rodents, 60%) belonged to the genus Meriones (mainly Persian jird, Meriones persicus). In total, 317 fleas were removed from trapped animals. Flea species belonged to Xenopsylla buxtoni, Xenopsylla nuttalli, Stenoponia tripectinata, Paraceras melis, Ctenophthalmus rettigi smiti, Rhadinopsylla bivirgis, Paradoxopsyllus grenieri, and Nosopsyllus iranus. Using the qPCR tests, five spleen samples from M. persicus were positive for F. tularensis. The qPCR tests were negative for the detection of Y. pestis and arenaviruses. Finally, all serum samples tested were negative for antibodies against Y. pestis and F. tularensis. Conclusions: F. tularensis was the only zoonotic agent detected in rodents captured in East Azerbaijan. However, the diversity of trapped rodents and fleas provides the potential for the spread of various rodent-borne viral and bacterial diseases in the studied areas.

Epidemiology of tularemia in the countries of the WHO Eastern Mediterranean Region (EMRO): A systematic review and meta-analysis

BACKGROUND

Francisella tularensis, the bacterium that causes tularemia, has been a persistent and widespread pathogen in various regions of the world for centuries. Francisella tularensis can affect humans and various domestic and wild animals. The current study aimed to determine the epidemiological status of tularemia in countries of the WHO Eastern Mediterranean Region (EMRO) through a systematic review and meta-analysis.

METHODS

All included studies were identified through a systematic search of online databases, including Scopus, PubMed, Web of Science, and EMBASE, through July 26, 2022, using keywords and suitable combinations. We focused on cross-sectional studies investigating the prevalence of F. tularensis. The weighted pooled prevalence was calculated using a random-effects model.

RESULTS

A total of 206 studies were identified, of which 20 were finally included in the analysis. The human seroprevalence of tularemia in WHO-EMRO countries was 6.2% (95% CI, 4.2 9.2). In the subgroup analysis, anti-F. tularensis antibodies were found in 6.92% and 5.5% of the high-risk individuals and Iran, respectively. The pooled prevalence of F. tularensis in environmental samples (water and soil) from the WHO-EMRO countries was 5.8% (9.4% by PCR and 0.5% by culture). In addition, 2.5% (95% CI, 0.2 0.22.7) of ticks in WHO-EMRO countries were positive for F. tularensis. The pooled prevalence of F. tularensis in rodents is 2.0% (1.1% by PCR and 3.7% by serology). In addition, 0.6% of domestic ruminants (0.4% by PCR and 2.4% by serology) were positive for F. tularensis in WHO-EMRO countries.

CONCLUSION

According to the results of the present study, tularemia is an endemic but neglected disease in the WHO-EMRO region. However, most studies on tularemia are limited to a few countries in this region. Studies on tularemia in human populations, reservoirs, and vectors have been conducted in all countries in the WHO-EMRO region to obtain more detailed information about the epidemiology of tularemia in these regions.

First molecular detection of Francisella tularensis in turtle (Testudo graeca) and ticks (Hyalomma aegyptium) in Northwest of Iran

Francisella tularensis, causative agent of tularemia, is a contagious zoonotic ailment. This study was aimed to molecularly detect F. tularensis in tortoise blood (n = 100) and ticks (n = 100) collected in the West Azerbaijan province, Iran suing a 16SrRNA gene of the Francisella genus through employment of the Nested-PCR technique. The identified ticks were s Hyalomma aegyptium by morphological analysis. Seven percent (with a 95% CI: 3.5%-13.75%) of animal blood samples yielded positive results for the presence of the Francisella. Meanwhile, the Francisella was identified in tick samples at a rate of fifteen percent (15%) (with a 95% CI: 9%-23%). The samples containing positive results were specifically classified as F. tularensis subsp. holarctica. The samples were taken from ticks belonging to the H. aegyptium species that were gathered in Oshnavieh, southern part of West Azerbaijan province, Iran. This research was aimed to validate the existence of F. tularensis in ticks found within the West Azerbaijan province. Consequently, it is vital to acknowledge the potential of these ticks to transmit the bacteria to both livestock and humans through tick bites in this specific area.

First report of Anaplasma spp., Ehrlichia spp., and Rickettsia spp. in Amblyomma gervaisi ticks infesting monitor lizards (Varanus begalensis) of Pakistan

Ticks pose significant health risks to both wildlife and humans due to their role as vectors for various pathogens. In this study, we investigated tick infestation patterns, tick-associated pathogens, and genetic relationships within the tick species Amblyomma gervaisi, focusing on its prevalence in monitor lizards (Varanus bengalensis) across different districts in Pakistan. We examined 85 monitor lizards and identified an overall mean intensity of 19.59 ticks per infested lizard and an overall mean abundance of 11.98 ticks per examined lizard. All collected ticks (n = 1019) were morphologically identified as A. gervaisi, including 387 males, 258 females, 353 nymphs, and 21 larvae. The highest tick prevalence was observed in the Buner district, followed by Torghar and Shangla, with the lowest prevalence in Chitral. Lizard captures primarily occurred from May to October, correlating with the period of higher tick infestations. Molecular analysis was conducted on tick DNA, revealing genetic similarities among A. gervaisi ticks based on 16S rDNA and ITS2 sequences. Notably, we found the absence of A. gervaisi ITS2 sequences in the NCBI GenBank, highlighting a gap in existing genetic data. Moreover, our study identified the presence of pathogenic microorganisms, including Ehrlichia sp., Candidatus Ehrlichia dumleri, Anaplasma sp., Francisella sp., Rickettsia sp., and Coxiella sp., in these ticks. BLAST analysis revealed significant similarities between these pathogenic sequences and known strains, emphasizing the potential role of these ticks as vectors for zoonotic diseases. Phylogenetic analyses based on nuclear ITS2 and mitochondrial 16S rDNA genes illustrated the genetic relationships of A. gervaisi ticks from Pakistan with other Amblyomma species, providing insights into their evolutionary history. These findings contribute to our understanding of tick infestation patterns, and tick-borne pathogens in monitor lizards, which has implications for wildlife health, zoonotic disease transmission, and future conservation efforts. Further research in this area is crucial for a comprehensive assessment of the risks associated with tick-borne diseases in both wildlife and humans.

Tularemia - a re-emerging disease with growing concern

Tularemia caused by Gram-negative, coccobacillus bacterium, Francisella tularensis, is a highly infectious zoonotic disease. Human cases have been reported mainly from the United States, Nordic countries like Sweden and Finland, and some European and Asian countries. Naturally, the disease occurs in several vertebrates, particularly lagomorphs. Type A (subspecies tularensis) is more virulent and causes disease mainly in North America; type B (subspecies holarctica) is widespread, while subspecies mediasiatica is present in central Asia. F. tularensis is a possible bioweapon due to its lethality, low infectious dosage, and aerosol transmission. Small mammals like rabbits, hares, and muskrats are primary sources of human infections, but true reservoir of F. tularensis is unknown. Vector-borne tularemia primarily involves ticks and mosquitoes. The bacterial subspecies involved and mode of transmission determine the clinical picture. Early signs are flu-like illnesses that may evolve into different clinical forms of tularemia that may or may not include lymphadenopathy. Ulcero-glandular and glandular forms are acquired by arthropod bite or handling of infected animals, oculo-glandular form as a result of conjunctival infection, and oro-pharyngeal form by intake of contaminated food or water. Pulmonary form appears after inhalation of bacteria. Typhoidal form may occur after infection via different routes. Human-to-human transmission has not been known. Diagnosis can be achieved by serology, bacterial culture, and molecular methods. Treatment for tularemia typically entails use of quinolones, tetracyclines, or aminoglycosides. Preventive measures are necessary to avoid infection although difficult to implement. Research is underway for the development of effective live attenuated and subunit vaccines.

Molecular Detection of Francisella tularensis Isolated from Ticks of Livestock in Kurdistan Region, Iraq

Background: Francisella tularensis is a Gram-negative bacterium that causes tularemia in both human and animals. Tularemia is a potential serious zoonotic disease that is transmitted by different routes, including tick bites. Materials and Methods: This study deals with investigating the prevalence of F. tularensis in the ticks of local animal farms in Kurdistan region since the farmers are normally in close contact with livestock. We used molecular methods for this purpose. A total of 412 tick and 126 blood samples were gathered from goat, sheep, and cow flocks. The existence of F. tularensis 16Sr RNA gene was examined in the samples using nested-PCR technique. Results: In the animal blood specimens, no F. tularensis was found. The incidence of F. tularensis was 1.7% (7 out of 412) in the tick samples, representing a very lower possibility of tuleremia infection. Moreover, the two subspecies of F. tularensis novicida and holarctica were identified based on the sequencing of pdpD and RD genes, respectively. The F. tularensis subsp. novicida was isolated from four species of ticks, Hyalomma anatolicum, Rhipicephalus annulatus, Rhipicephalus sanguineus, and Ornithodoros spp., whereas the F. tularensis subsp. holarctica was isolated from Haemaphysalis parva and Hyalomma dromedarii species of ticks. Conclusion: Although its prevalence is very low, the isolation of F. tularensis subsp. holarctica from the ticks of farm animals suggests possible transmission of Tularemia through tick bite in Kurdistan region of Iraq. Ref: IR-UU-AEC-3/22.

Monitoring of hard tick parasitism in domestic ruminants: A scale evidence for policymakers

Domestic ruminants such as camels, cattle, goats, and sheep represent a substantial part of the global world economy. Hard ticks are well-known as obligatory bloodsucking ectoparasites of domestic ruminants. Policymakers need to get results that show the global distribution of tick genera and species, their parasitic levels, and their roles as disease vectors in camels, cattle, goats, and sheep. Iran is endemic to a broad range of hard tick-borne diseases. A study that reviews the tick genera and species, life stage, seasonal and attachment site parasitism levels, the global mean ranks of tick species parasitism rates and records, and their distribution in target animals would be of particular importance. Accordingly, this review aims to summarize the above objectives. After evaluating the identified articles, 147 were selected to be part of the survey based on the study objectives. Globally, tick parasitism levels were 28.7, 29.9, 36.0 and 47.6% for goats, cattle, sheep, and camels, respectively. The tick parasitism trends have exhibited an increasing trend for camels and sheep over the years while remaining constant for cattle and goats, indicating that current tick control measures are not being properly followed. Ticks tend to parasitize females more than males because males are more resistant to certain pests than females. The distribution of tick genera and species, their parasitism levels, and their roles as disease vectors provided. This information addresses the needs of decision-makers to make decisions.

Francisella and tularemia in western Asia, Iran: a systematic review

Tularemia or rabbit fever is a transmissible disease from animals, rodents, and insects to human populations that is caused by Francisella tularensis. Epidemiological studies showed that tularemia is endemic throughout most different regions of the world. Recent evidence documented the transmission of the F. tularensis in a different part of Asia. Because there is no updated review information for tularemia in Iran, we performed this systematic review. In this study, we systematically explored biomedical databases (Google Scholar, Scopus, PubMed, and Web of sciences) to identify epidemiology, reservoirs, and carriers of Francisella in animal and human clinical specimens from 2010 to 2020, either in English or in Persian. Different studies have shown the different frequencies of F. tularensis among human and animal resources in eighteen provinces of Iran. In total, 1242 human clinical specimens, 1565 animal samples, and 355 environmental water samples were investigated to find F. tularensis in different provinces of Iran. According to the collected documents, 94 human clinical samples, 69 water samples, and 26 animal specimens were introduced as positive samples for the F. tularensis. According to studies, thirteen species of rodent and hare presented as an inter-epizootic reservoir. Only one species of tick (D. marginatus) was introduced as a vector for Francisella in Iran. According to these results, it is essential for exclusive attention to the prevalence of F. tularensis in different provinces of Iran. Furthermore, special planning should be done for prevention, control of the outbreak, and proper treatment of the tularemia.

A case report of ulceroglandular tularemia caused by Francisella tularensis subsp. holarctica in Iran

BACKGROUND

Tularemia is a zoonotic disease that has been reported in many countries of the Northern Hemisphere. However, in some countries, such as Iran, this disease has been neglected by the health care system, and it is under-reported.

CASE PRESENTATION

Here we report an unusual case of ulceroglandular tularemia occurring in a 35-year-old woman who presented with a skin lesion of the left flank, inguinal lymphadenopathy, and an abdominal abscess. The serological and real-time PCR tests for tularemia were positive for this patient, and infection by Francisella tularensis subsp. holarctica was confirmed.

CONCLUSIONS

It is necessary to implement various educational programs to increase the awareness of physicians with tularemia.