Typhus Research Articles

Acaricidal Activity of Colchicum autumnale (autumn crocus) Extract against Hyalomma spp. In vitro.

Hyalomma spp. is responsible for the transmission of protozoan, bacterial, rickettsial, and viral diseases and causes huge economic loss to the livestock industry.Recently, there is a wide number of promising attempts to evaluate and use herbal preparations for ticks control.This study aimed to evaluate the acaricidal activity of aqueous and ethanol extracts of Colchicum autumnale (C. autumnale) rhizome and leaf against the Hyalomma spp. in vitro. The acaricidal activities of the Colchicum leaf aqueous (CLA), Colchicum leaf ethanolic (CLE), Colchicum rhizome aqueous (CRA), and Colchicum rhizome ethanolic (CRE) extracts were evaluated at concentrations of 50, 100, and 150 mg/ml and controls (distilled water and Cypermethrin) following 0.25, 0.5, 0.75, and 1 h of exposure. It is worth mentioning that the spraying method was used in these experiments. Data were analyzed through GraphPad Prism 5 software. In addition, the chemical composition of aqueous leaf extract was analyzed using gas chromatography-mass spectrometry (GC–MS). The carbamodithioic acid (30.04%) was the major chemical constituent identified. Based on the results, CLA, CLE, CRA, and CRE extracts had an acaricidal effect; however, this effect was more potent in CLE. The CLE extract showed a 100% mortality rate at 50, 100, and 150 mg/ml concentrations and 1 h of exposure. The effectiveness of CRA on the Hyalomma spp. was very low. The median lethal concentration (LC50) values were obtained at 100 mg/ml. The results indicated that C. autumnaleleaves contained potent acaricidal ingredients and might provide new acaricidal compounds for the effective control of Hyalomma spp. However, further studies are required to evaluate the efficacy of C. autumnale in vivo.

Mental Health Outcomes Among Health Care Workers Exposed to Covid-19 Pandemic, Qalyoubia Governorate: Cross-Sectional Survey

Background: The pandemic caused by novel coronavirus disease 2019 (COVID-19) is considered the worst health crisis facing the entire world today. At the topmost of this crisis are the healthcare workers (HCWs) who are working to maintain well-being of all people. COVID-19 pandemic added more and more stress to healthcare workers in particular, depending on their work position. Objective: To assess mental health outcomes among HCWs dealing with confirmed or suspected COVID-19 patients. Methods: This is cross-sectional, hospital-based survey study conducted between Feb 6 and April 28, 2021. A total of 548 HCWs participated in the study. Mental health impact was assessed by using the 9- item Patient Health Questionnaire (PHQ-9), the 7-item Generalized Anxiety Disorder (GAD-7) and the 7-item Insomnia Severity Index (ISI) questionnaires. Multivariable logistic regression analysis was done to determine the risk factors of mental health outcomes. Results: Among the 548 HCWs surveyed;64.8% were nurses and 50.0% aged from 26-30 years old. About 52.0% worked in Benha University Hospital, 21.2% worked in Toukh Fever Hospital, and 26.8% worked in Qaha Central Hospital. A considerable proportion of HCWs had symptoms of anxiety, depression and insomnia. Nurses, workers aged from 26-30, those working in Qaha Central Hospital and those who had shift hours from 7–10 experienced more severe symptom levels of depression, anxiety, and insomnia. Nurses were associated with severe symptoms of anxiety, depression and insomnia. Conclusion: The COVID-19 pandemic represents a new working challenge for HCWs and intervention strategies to prevent depression and anxiety to reduce the risk of adverse mental health outcomes are needed. [ABSTRACT FROM AUTHOR] Copyright of Egyptian Journal of Hospital Medicine is the property of Egyptian Journal of Hospital Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Clinical characteristics and mortality rates associated with MERS-COV-2 infection among patients from Sohag Governorate, Egypt

Objective This study aimed to investigate the impact of different clinical characteristics associated with MERS-CoV2 infection and mortality among patients from Sohag Fever Hospital, Sohag Governorate, Egypt. Background Currently, coronavirus disease 2019 (COVID-19) is one of the dangerous life-threatening diseases prevalent worldwide. Different clinical studies were carried out to increase the range of diagnosis level and predict its mortality rates in terms of different clinical and nonclinical characteristics. Patients and methods In the current case–control study, a hundred patients, hospitalized in Sohag Fever Hospital, Sohag Governorate, Egypt, were recruited in the period from October 2020 to December 2020. Sixty-four patients were positive PCR for COVID-19, while the other 34 were negative and were recruited as controls. Data included the demographic and clinical information such as their ages, place of residence, and infection symptoms in addition to laboratory investigation results such as complete blood count, differential blood count and hemoglobin (Hb) level, and clinical data such as %O2 saturation, respiration rates per minute, and body temperature were collected. The data were statistically interpreted. Results PCR positivity was more prevalent among females (73.2%) and urban residents (67%). Lower %O2 (45.2%, 52.8%), higher white blood cell counts (72.2%, 27.8%), and lower Hb levels (69.8%, 31.2%) showed significantly different distributions among male and female participants, respectively. PCR results and chest computed tomographic scan were significantly affected by %O2 saturation (87.1%, 45.2%), body temperature (100%, 53.3%), respiration rate (100%, 47.3%), and increase in the number of symptoms (100%, 22.2%), respectively. It was found that Hypertension (95% confidence of intervals (CI)= 0.061–0.245) and %O2 saturation values (95% CI= 0.077–0.523) are significantly related to the higher mortality rates due to MERS-COV-2 infection. Conclusion The study revealed the impact and correlation between the severity and risk of mortality of COVID-19 with different clinical markers such as lower %O2 saturation, high body temperature, higher respiration rate, higher white blood cell count, and lower Hb levels. Further studies might be required to investigate the effect of more clinical data and comorbidities associated with the viral infection.

Analysis of Ear, Nose and Throat Manifestations in COVID-19 Patients.

Introduction Coronavirus disease 2019 (COVID-19) has dramatically spread all over the world, crossing the borders of all countries. It is presented mainly by lower respiratory tract symptoms such as fever, cough, dyspnea, and chest tightness. However, COVID-19 causes different upper respiratory tract-related symptoms including nasal congestion, sore throat, and olfactory dysfunction. Objective To discuss different ear, nose and throat (ENT) manifestations in COVID-19-positive patients and their relation to other manifestations and to the severity of COVID-19. Methods We detected ENT manifestations in polymerase chain reaction (PCR)-confirmed positive COVID-19 patients at Zagazig Isolation Hospitals (Zagazig University hospitals, Zagazig Chest hospital, Al-Ahrar hospital, and Zagazig Fever hospital) with proportional allocation in the period from April 15 to June 15, 2020. All patients were subjected to full history taking and COVID-19 was categorized into 4 classes of severity after all patients underwent computed tomography (CT) of the chest. Afterwards, the collected data was analyzed and compared. Results Among the included 120 COVID-19 patients, the most frequent reported ENT manifestations were; sore throat (30%), nasal congestion (28.3%), nasal obstruction (26.7%), sneezing (26.6%), headache (25%), smell and taste dysfunction (25%), rhinorrhea (20%), upper respiratory tract infection (URTI) (15%), and tonsil enlargement (10%). The most common non-ENT manifestations were fever (88.3%), cough (63.3%), and dyspnea (45%). Conclusion Fever and cough are the dominant symptoms of COVID-19, but ENT manifestations for COVID-19 are common and should be a part of the suspected clinical criteria for COVID-19, particularly if the nasal examination was nonsignificant. The most common symptoms are sore throat, followed by nasal congestion and obstruction, headache, and lastly, olfactory dysfunction.

PRIMEIRO REGISTRO DO ÁCARO Psoralges libertus Trouessart, 1896 EM CANAL AUDITIVO DE TAMANDUÁ-BANDEIRA Myrmecophaga tridactyla Linnaeus, 1758 DE VIDA LIVRE

Zoological parks are an excellent source of biological material for research, as they often receive free-living wild animals. The present report discusses the occurrence of mites in the ear canal in a free-living anteater in the Metropolitan Region of Sorocaba, forwarded to the Sorocaba Zoo. During the clinical examination of the animal ectoparasites were located and collected. The mites were collected from the ear canal and were deposited in plastic pots with 70% alcohol, then sent to the National Reference Laboratory for Rickettsial Diseases Vectors (LIRN) of the Oswaldo Cruz Institute (IOC), Oswaldo Cruz Foundation (FIOCRUZ). Using taxonomic specific keys and with the aid of a microscope, the species Psoralges libertus Trouessart, 1896 was morphologically identified. This species was reported in another species from the Order Pilosa, but it is the first record of Psoralges libertus parasitizing a free-living Myrmecophaga tridactyla Linnaeus, 1758.

Affordable measures to monitor and alarm nosocomial SARS-CoV-2 infection due to poor ventilation.

Since the coronavirus disease 2019 (COVID‐19) outbreak, the nosocomial infection rate worldwide has been reported high. It is urgent to figure out an affordable way to monitor and alarm nosocomial infection. Carbon dioxide (CO2) concentration can reflect the ventilation performance and crowdedness, so CO2 sensors were placed in Beijing Tsinghua Changgung Hospital's fever clinic and emergency department where the nosocomial infection risk was high. Patients’ medical records were extracted to figure out their timelines and whereabouts. Based on these, site‐specific CO2 concentration thresholds were calculated by the dilution equation and sites’ risk ratios were determined to evaluate ventilation performance. CO2 concentration successfully revealed that the expiratory tracer was poorly diluted in the mechanically ventilated inner spaces, compared to naturally ventilated outer spaces, among all of the monitoring sites that COVID‐19 patients visited. Sufficient ventilation, personal protection, and disinfection measures led to no nosocomial infection in this hospital. The actual outdoor airflow rate per person (Q c) during the COVID‐19 patients’ presence was estimated for reference using equilibrium analysis. During the stay of single COVID‐19 patient wearing a mask, the minimum Q c value was 15–18 L/(s·person). When the patient was given throat swab sampling, the minimum Q c value was 21 L/(s·person). The Q c value reached 36–42 L/(s·person) thanks to window‐inducted natural ventilation, when two COVID‐19 patients wearing masks shared the same space with other patients or healthcare workers. The CO2 concentration monitoring system proved to be effective in assessing nosocomial infection risk by reflecting real‐time dilution of patients’ exhalation.

Selenium status of patients with tick-borne rickettsiosis in the south of the Khabarovsk territory

Selenium status of patients with tick-borne rickettsiosis in the south of the Khabarovsk territory

The Value of Combined Measuring of the Cerebrospinal Fluid Lactate and ‎Serum Procalcitonin in Diagnosis of Acute Bacterial Meningitis ‎

Backgroundand study aim:The differential diagnosis between bacterial meningitis and aseptic meningitis is a critical clinical issue and ‎searching for reliable and valid markers is required. This work aimed to assess the role of the combined ‎measuring of CSF lactate and serum procalcitonin in the diagnosis of acute bacterial meningitis‎‎‎. Patients and Method:‎A cross-sectional study including 42 meningitis patients was conducted at Zagazig Fever Hospital and Zagazig ‎University Hospitals in the period from November 2018 to June 2019, Patients were divided according to their ‎final diagnosis into two groups; group I included 13 patients with bacterial meningitis ( positive CSF bacterial ‎culture and/or Gram stain ), group II included 29 patients with aseptic meningitis (negative CSF bacterial ‎culture and Gram stain), The data collection sheet included clinical assessments, lumbar puncture with CSF ‎analysis, CSF lactate level testing, and Serum procalcitonin level testing‎‎.‎ Results: One hundred five of house officer participated Serum procalcitonin and CSF lactate levels were significantly higher in the bacterial meningitis group (1.16 ‎‎±1.24, 7.5 ± 6.6, respectively) than patients with aseptic meningitis (0.059 ± 0.04, 3.98 ± 2.1, respectively). ‎The measuring of both serum procalcitonin and CSF lactate levels had got a higher sensitivity, specificity, and ‎accuracy (96.6%, 76.9%, 90.9% respectively) for the diagnosis of bacterial meningitis more than measuring ‎either of them only‎‎‎. Conclusion: The combined measuring of both serum procalcitonin and CSF lactate levels is highly accurate in the diagnosis ‎of bacterial meningitis cases and helps to differentiate bacterial meningitis from aseptic meningitis‎‎‎‎.

Effect of Temperature on Host Preference in Two Lineages of the Brown Dog Tick, Rhipicephalus sanguineus.

Rhipicephalus sanguineus is a species complex of ticks that vector disease worldwide. Feeding primarily on dogs, members of the complex also feed incidentally on humans, potentially transmitting disease agents such as Rickettsia rickettsii, Rickettsia conorii, and Ehrlichia species. There are two genetic Rh. sanguineus lineages in North America, designated as the temperate and tropical lineages, which had occurred in discrete locations, although there is now range overlap in parts of California and Arizona. Rh. sanguineus in Europe are reportedly more aggressive toward humans during hot weather, increasing the risk of pathogen transmission to humans. The aim of this study was to assess the impact of hot weather on choice between humans and dog hosts among tropical and temperate lineage Rh. sanguineus individuals. Ticks in a two-choice olfactometer migrated toward a dog or human in trials at room (23.5°C) or high temperature (38°C). At 38°C, 2.5 times more tropical lineage adults chose humans compared with room temperature, whereas temperate lineage adults demonstrated a 66% reduction in preference for dogs and a slight increase in preference for humans. Fewer nymphs chose either host at 38°C than at room temperature in both lineages. These results demonstrate that risk of disease transmission to humans may be increased during periods of hot weather, where either lineage is present, and that hot weather events associated with climatic change may result in more frequent rickettsial disease outbreaks.

Analysis and simulation of mathematical model for typhus disease in Makassar

The aims of the research is to build a mathematical model for typhus; Analyse and determine the basic reproduction number of the model; model simulations to predict the number of Typhus cases in Makassar City. This stage of the study examines the mathematical model of Typhus transmission by including food and flies as variables, which are the Susceptible-Exposed-Infected-Recovered (SEIR) model; analysed the SEIR model using the matrix generation method, then the model simulation using Maple with secondary data on the number of Typhus cases in Makassar City obtained from the Makassar Health Office. The results obtained are the SEIR model for typhus transmission by including flies and food as a variable which is an eight dimension non-linear differential equation model. This study also provides the analysis results of the SEIR model that Makassar is not worried an area Makassar for Typhus disease, this means the disease Typhus still exists in Makassar, while the calculation results of the basic reproduction number is .R0=0.137≤1, it can be concluded that the spread of typhus in Makassar is at an alarming stage, because a person suffering from typhus does not cause another person to suffer from Typhus. Model simulation results can predict the number of cases of Typhus so that early prevention can be done immediately and become the government’s attention to prevent the spread of typhus in Makassar City

Zoonotic Rickettsia Species in Small Ruminant Ticks From Tunisia.

Tick-borne rickettsioses present a significant public health threat among emerging tick-borne diseases. In Tunisia, little is known about tick-borne Rickettsia pathogens. Therefore, the aim of this study was to investigate the presence of Rickettsia species in small ruminant ticks from Tunisia. Adult ticks (n = 694) were collected from goats and sheep in northern Tunisia. Obtained ticks were identified as Rhipicephalus turanicus (n = 434) and Rhipicephalus sanguineus sensu lato (n = 260). Selected ticks (n = 666) were screened for the presence of Rickettsia spp. by PCR targeting a partial sequence of the ompB gene followed by sequence analysis. Rickettsial DNA was detected in 122 (18.3%) tested tick samples. The infection rates in Rh. turanicus and Rh. sanguineus s.l. ticks were 23.4 and 9.5%, respectively. The overall prevalence of rickettsial DNA was markedly higher in ticks collected from goats (23.2%) compared to those infesting sheep (7.9%). The detection of rickettsial DNA was significantly higher in ticks from the governorate of Beja (39.0%) than those from the governorate of Bizerte (13.9%). Two additional genes, the outer membrane protein A gene (ompA) and the citrate synthase gene (gltA), were also targeted for further characterization of the detected Rickettsia species. Genotyping and phylogenetic analysis based on partial sequences (n = 106) of the three different genes revealed that positive ticks are infected with different isolates of two Spotted Fever Group (SFG) Rickettsia, namely, Rickettsia massiliae and Rickettsia monacensis, closely related to those infecting camels and associated ticks from Tunisia, and humans and small ruminant ticks from neighboring countries like Italy, France, and Spain.

Assessing scrub typhus and rickettsioses transmission risks in the Chiang Rai province of northern Thailand

BackgroundScrub typhus is an important disease in the Asia-Pacific countries with increasing relevance for public health worldwide. Entomological risk assessment for scrub typhus and rickettsial disease in Phu Chi Fah village-Chiang Rai was performed to determine areas at greatest risk for disease transmission in order to increase awareness of diseases to travelers and healthcare workers. MethodsFrom 2016 to 2018, rodents and chiggers were collected from 7 sites covering residential, grassland, and forest areas to determine the prevalence of pathogen of interest. The correlation between land type and vector-host-pathogen interaction system was investigated. ResultHigh prevalence of O. tsutsugamushi-infected and Rickettsia-infected chiggers was observed especially in areas with grassland and forest ecotones. Chigger and rodent species composition were negatively associated with the level of human disturbance. Increased density of rodents was responsible for a higher abundance of chigger population and increased prevalence of O. tsutsugmaushi infection in chigger in the following year. ConclusionCommunities in the study areas have an increased exposure risk to scrub typhus and potentially spotted fever group rickettsiosis. Travellers to this endemic area should pay more attention pathogen risks so as to avoid vector and disease exposure. Seasonal rodenticidal activity may help migitate the risk of pathogen transmission.

High prevalence and low diversity of chigger infestation in small mammals found in Bangkok Metropolitan parks.

Chiggers are recognized as vectors of scrub typhus disease caused by the bacteria, Orientia tsutsugamushi. The risk of disease exposure is mainly related to chigger bites when humans or animals roam into vector-infested habitats. In big cities, urban public parks could provide areas for the animal-human interface and zoonotic pathogen transmission. The ecology and epidemiology of urban scrub typhus are still poorly understood in Thailand. Small mammals were trapped and examined for chigger infestation in urban public parks across metropolitan Bangkok, Thailand. We found a high prevalence of infestation (76.8%) with surprisingly low diversity. Two chigger species, Leptotrombidium deliense and Ascoschoengastia indica, were identified using morphological characteristics and molecular confirmation. The generalized linear model identified host intrinsic variables (i.e. body mass index) with host density, habitat composition and open field as the extrinsic factors explaining the abundance of chigger infestation. The bacteria O. tsutsugamushi was not detected in chiggers (90 chigger-pooled samples) and animal host tissues (164 spleen samples). However, the existence of chigger vectors calls for the Bangkok Metropolitan Administration and public health authorities to develop a comprehensive scrub typhus monitoring and prevention strategy in the parks and nearby communities.

Inferring the Potential Distribution of an Emerging Rickettsiosis in America: The Case of Rickettsia parkeri.

Tick-borne rickettsioses represent a severe public health problem that has increased in recent decades by several activities that place human populations in contact with a wide range of vectors. In particular, Rickettsia parkeri, an eschar-associated spotted fever agent, represents an emerging pathogen that has been gradually identified throughout America. In the present work, we compiled an occurrence database of these bacteria, as well as its vectors, in order to identify the potential distribution of these bacteria and to detect the risk areas where this emerging pathogen may be circulating. The results show the at-risk areas to be broad regions in Central America, on the coast of Venezuela, Colombia, Ecuador, Peru, and Chile, part of Brazil and Argentina, and the greater part of Bolivia, Paraguay, and Uruguay. Particularly, in Mexico, conditions exist for widespread dissemination. Our results must be considered for the establishment of active acarological surveillance in previously unsampled areas, as well as the establishment of prevention measures for vulnerable populations and risk groups participating in outdoor activities that can place them in contact with this pathogen.

Hemophagocytic Lymphohistiocytosis Associated with Coinfection of Scrub Typhus and Dengue Fever in a Child: A Case Report

Hemophagocytic Lymphohistiocytosis Associated with Coinfection of Scrub Typhus and Dengue Fever in a Child: A Case Report

The identification of Salmonella sp. in “cilok” road food in campus area of Jember University

Snack is very broad with target consumers of school-age children from elementary school to tertiary level. Cilok is one of the favorite snacks for students in the campus area of Jember University, which is often a substitute food when it is not yet eating. Foodborne illness is a food-borne disease. Bacterial contamination of food causes plague and death in foodborne diseases. One that causes pathogens that cause foodborne diseases is Salmonella typhi bacteria. Salmonella typhi is a gram-negative bacteria that attacks the intestines and liver which causes typhus or typhoid fever. The purpose of this study was to determine the presence of Salmonella typhi bacteria in the sample. The research design carried out is descriptive. The research method begins with random sampling, making agar medium, enrichment of samples using Nutrient Borth, Salmonella Test with SSA (Salmonella-Shigella Agar) media. The results showed that Salmonella typhi was found in samples a, c, e, f, g, h, and i. The presence of Salmonella typhi is indicated by the growth of bacteria on SSA media as a selective medium for Salmonella typhi. In the results of the study there were seven samples from eleven samples found Salmonella typhi.

PSYCHOLOGICAL IMPACT OF COVID-19 PANDEMIC ON HEALTH CARE WORKERS

Introduction: Healthcare staffs are first-line fighters who handle COVID-19 patients.They face a high risk of infection every day, and are subject to long and distressingwork hours in order to meet health needs. Aim of work: To evaluate the psychologicalimpact of COVID-19 pandemic on health care workers (HCWs). Materials andMethods: All categories of health care workers in Egypt were invited to participatein the study through sharing the link to online professional groups between 21st Juneto 9th July 2020. The survey included a self-administered- Arabic questionnaireincluding information related to socio- demographic characteristics, medical historyincluding diseases and medications, work characteristics and COVID -19 experienceof the studied participants. The survey also included validated Depression, Anxiety,and Stress Scales (DASS-21) and 7 items work-related burnout Copenhagen BurnoutInventory (CBI). Results: The total number of health care workers who shared in thestudy was 764. There were psychological disorders of varying degrees in the formof depression (41.5%), anxiety (67%), and stress (27.7 %). Working as nurses, age <40 years, changing vacation plans during COVID 19, shift work, less than 10 yearsof experience, single HCWs were the most significant factors for predicting stress.Conclusion: The results concluded that health care workers had varying degrees ofpsychological stress related to the job, particularly those in direct relationships with COVID-19 patients and those who work in fever and chest hospitals. Psychologicalsupport for promoting mental well-being in health care workers exposed to COVID-19should be implemented immediately, particularly for female, nurses and frontlinehealth care workers.

Ocular manifestation of rickettsial disease in South Indian population.

Purpose:The aim of this work was to study the ocular manifestations and its management in spotted fever and typhus group of rickettsial disease.Methods:A retrospective analysis of 50 patients with serologically confirmed Rickettsial disease. In all patients, relevant history, investigations and treatment details were collected and they underwent complete ophthalmic evaluation including measurement of best-corrected visual acuity, anterior segment examination and dilated fundus examination.Results:Mean age was 12.5 ± 8.99 years. Of the 50 patients, 40 patients were ≤18 years of age and 27 (54%) had ocular involvement. Out of 27 patients, bilateral involvement was seen in 10 patients. Most of the patients had no ocular symptoms. Ocular findings included, Retinal vasculitis 6 (22.22%); macular edema 4 (14.81%); vasculitis with macular edema 1 (3.7%); Retinitis 7 (25.92%); Papilloedema 6 (22.22%); Papilloedema with 6th cranial nerve palsy 1 (3.7%); Isolated 6th cranial nerve palsy 1 (3.7%) and optic neuritis 1 (3.7%). Ocular involvement was more common in double antigen group (68%) than spotted fever group (50%) or Scrub typhus group (21%) (P = 0.01). Ocular involvement was seen in 94% of the patients with CNS involvement. Cases with bilateral involvement (P = 0.01), pediatric age group (P = 0.01) and CNS involvement (P = 0.02) had poor visual outcome.Conclusion:Rickettsioses patients can have ocular manifestations with predominant posterior segment involvement during acute phase of illness. Ocular involvement was more common in the double antigen group. For any patient who presents with fever and rash living in endemic area, ophthalmic evaluation should be part of routine checkup during the acute phase of illness associated with less frequent ocular symptoms.

Mitochondrion-Dependent Apoptosis Is Essential for Rickettsia parkeri Infection and Replication in Vector Cells

ABSTRACTApoptosis is an innate immune response induced by infection in eukaryotes that contributes significantly to protection from pathogens. However, little is known about the role of apoptosis in the interactions of arthropod vectors with the rickettsiae that they transmit. Rickettsia spp. are vector-borne obligately intracellular bacteria and display different degrees of virulence in their eukaryotic hosts. In this study, we found that infection with Rickettsia parkeri (Rp) activated the apoptosis pathway in an Amblyomma americanum tick cell line (AAE2), as evidenced by the loss of phospholipid membrane asymmetry and DNA fragmentations. Additionally, infection with Rp also led to apoptosis activation in cell lines of different tick species. Interestingly, suppressing apoptosis decreased Rp infection and replication, while the activation of apoptosis increased Rp accumulation at the early stage of infection. Moreover, mitochondrion-dependent apoptosis was essential for Rp infection and replication in vector cells, and apoptosis induction required intracellular rickettsia replication. We further showed that Rp utilizes two different survival strategies to modulate apoptosis in the arthropod vectors and mammalian host cells. There was no direct correlation between apoptosis activation in vector cells and rickettsial pathogenicity. These novel findings indicate a possible mechanism whereby apoptosis facilitates infection and replication of a Rickettsia sp. in an arthropod vector. These results contribute to our understanding of how the vector's responses to pathogen infection affect pathogen replication and therefore transmission.IMPORTANCE Rickettsioses, infections caused by the genus Rickettsia, are among the oldest known infectious diseases. Ticks are essential arthropod vectors for rickettsiae, and knowledge about the interactions between ticks, their hosts, and pathogens is fundamental for identifying drivers of tick-borne rickettsioses. Despite the rapid development in apoptosis research with rickettsiae, little is known regarding the role of apoptosis in the interactions between Rickettsia spp., vertebrate hosts, and arthropod vectors. Here, we demonstrated that mitochondrion-dependent apoptosis is essential for rickettsial infection and replication in vector cells and that apoptosis induction requires intracellular rickettsial replication. However, rickettsial pathogenicity is not linked with apoptosis activation in tick cells. Our findings improve understanding of the apoptosis mechanism in arthropods exploited by rickettsiae and also the potential to discover specific targets for new vaccines and drugs to prevent or treat rickettsial infections.

Occurrence of Anti-Rickettsia spp. Antibodies in Hospitalized Patients with Undifferentiated Febrile Illness in the Southern Region of Kazakhstan.

Undifferentiated febrile illness still represents a demanding medical problem all over the world, but primarily in low- and middle-income countries. Scientific and clinical investigations related to undifferentiated febrile illness and rickettsial diseases in Kazakhstan are lacking. This study reflects the investigation of antibodies against spotted fever group (SFG) and typhus group (TG) rickettsiae in patients with undifferentiated febrile illness in the southern region of Kazakhstan (Almaty and Kyzylorda oblasts). Paired serum samples were gathered from 13 hospitals in these two oblasts and explored for the presence of IgM and IgG antibodies against typhus group and IgG antibodies against spotted fever group rickettsiae using ELISA. Patient's questionnaires were statistically analyzed. In total, 802 inpatients from Almaty (N = 9) and Kyzylorda (N = 4) hospitals were included in this research. Based on ELISA results, 250 patients out of 802 (31.2%) from both oblasts had IgG antibodies against SFG rickettsiae. Results from 11 (1.4%) patients indicated acute infection with tick-borne rickettsiosis. Regarding TG rickettsiae (R. typhi), a past infection was detected in 248 (30.9%) febrile patients and acute infection in 22 (2.7%) patients in the two selected oblasts. The data indicated that SFG and TG rickettsioses are present in Kazakhstan. Kazakh physicians should be aware of these emerging diseases in both investigated oblasts because the occurrence of these diseases is not suspected during day-to-day clinical practice. The identification of rickettsial pathogens and implementation of modern laboratory methods for the diagnostics of rickettsioses are in need throughout Kazakhstan.