Typhus Research Articles

Tick-Borne Rickettsioses in the Iberian Peninsula.

Tick-borne rickettsioses (TBR) are caused by obligate, intracellular bacteria of the spotted-fever group (SFG) of the genus Rickettsia (Order Rickettsiales), transmitted by hard ticks. TBR are one of the oldest known vector-borne zoonoses and pose a threat to both human and animal health, as over the years, new SFG Rickettsia spp. have been reported worldwide with the potential to be human pathogens. In Portugal and Spain, the countries that constitute the Iberian Peninsula, reported TB rickettsiae causing human disease include Rickettsia conorii conorii, Rickettsia conorii israelensis, Rickettsia slovaca, Rickettsia raoultii, Candidatus Rickettsia rioja, Rickettsia sibirica mongolitimonae, and Rickettsia monacensis. An allochthonous case of TBR caused by Rickettsia massiliae, described in Spain, points to the need to monitor disease epidemiology, to predict risks of exposure and spread of disease, and taking into account globalization and climate changes. This review aims to provide up-to-date information on the status of TBR in the Iberian Peninsula, as well as to show the importance of a national and international collaborative epidemiology surveillance network, towards monitoring Rickettsia spp. circulation in both Portugal and Spain.

Occupational health surveillance and detection of emerging occupational diseases among Taiwan farmers, through analysis of national-based farmers' and medico-administrative databases.

The purpose of this study was to identify occupational injuries and diseases associated with agriculture in Asia, to provide a reference for prevention and hypotheses for future research. We matched data on agricultural workers (n = 963,124) enrolled in Taiwan's national Farmers Health Insurance since its inception in 1989, to general population controls of the same age, gender, and township. The study population was linked to the National Health Insurance Research Database from 2001 to 2016 for inpatient cases. Logistic regression was used to assess odds ratios for outcomes. Farmers had 2.76 times the risk of mycotic corneal ulcer (95% CI: 1.96-3.87) and 1.65 times the risk of typhus fever infections (95% CI: 1.47-1.85) compared to the general population. The odds ratio for poisonous animal bites was 2.22 (95% CI: 2.07-2.38), for falling into a storm drain or manhole was 2.04 (95% CI: 1.30-3.20), and for toxic effects from pesticides was 2.01 (95% CI: 1.92-2.11). The toxic effects of organophosphate and carbamate insecticides were correlated with the cultivation of rice, fruit trees, and flowers. Q fever and motorcycle accidents were associated with fruit tree cultivation. The study identifies agricultural occupational injuries and diseases that may inform occupational health policy and the development of prevention priorities to prevent occupational hazards for farmers.

Biology, Systematics, Microbiome, Pathogen Transmission and Control of Chiggers (Acari: Trombiculidae, Leeuwenhoekiidae) with Emphasis on the United States.

Chiggers are the larval stage of Trombiculidae and Leeuwenhoekiidae mites of medical and veterinary importance. Some species in the genus Leptotrombidium and Herpetacarus vector Orientia species, the bacteria that causes scrub typhus disease in humans. Scrub typhus is a life-threatening, febrile disease. Chigger bites can also cause dermatitis. There were 248 chigger species reported from the US from almost every state. However, there are large gaps in our knowledge of the life history of other stages of development. North American wide morphological keys are needed for better species identification, and molecular sequence data for identification are minimal and not clearly matched with morphological data. The role of chiggers in disease transmission in the US is especially understudied, and the role of endosymbionts in Orientia infection are suggested in the scientific literature but not confirmed. The most common chiggers in the eastern United States were identified as Eutrombicula alfreddugesi but were likely misidentified and should be replaced with Eutrombicula cinnabaris. Scrub typhus was originally believed to be limited to the Tsutsugamushi Triangle and the chigger genus, Leptotrombidium, but there is increasing evidence this is not the case. The potential of Orientia species establishing in the US is high. In addition, several other recognized pathogens to infect humans, namely Hantavirus, Bartonella, Borrelia, and Rickettsia, were also detected in chiggers. The role that chiggers play in these disease transmissions in the US needs further investigation. It is possible some of the tick-borne diseases and red meat allergies are caused by chiggers.

Clinical Spectrum and Outcome of Scrub Typhus Patients in a Tertiary Care Teaching Hospital of Western Maharashtra

Introduction: Acute febrile illness (AFI) is the most common presenting complaint in the emergency and outpatient clinics in developing countries. Scrub typhus is currently one of the most covert re-emerging infections and it is one of the commonly occurring rickettsial diseases in India. Objectives: To determine the clinical profile and outcome of scrub typhus patients admitted at a tertiary care centre of western Maharashtra for treatment. Material and Method: Present descriptive cross sectional study conducted over period of three years from October 2019 to October 2022. Study commenced after obtaining Institutional Ethical Permission (IEC). Clinically suspected patients undergone Weil-Fliex test followed by IgM ELISA for confirmation of diagnosis. Total 148 patients were included as inclusion and exclusion criteria. Results: Out of 148 patients 58.10% (86) and 41.89% (62) were male and female respectively. The commonest age group of patients was 21 to 30 years. Fever was the most common (81.75%) symptom and eschar (skin lesion) was seen in 16.21% (24) patients. Conclusion: Scrub typhus is an important cause of undifferentiated acute febrile illness should be considered in the differential diagnosis of pyrexia of unknown. Adequate knowledge about demographic and clinical profile scrub typhus helps in early diagnosis.

Incidence of hepatitis C virus infection among people living with HIV: An Egyptian cohort study.

Egypt used to have one of the highest hepatitis C virus (HCV) infection prevalence rates worldwide, with an estimated HCV prevalence of around 4.5% to 6.7%. To determine the HCV infection incidence rate amid Egyptian patients living with HIV. A total of 460 HIV-positive patients were recruited in a retrospective cohort study from Imbaba Fever Hospital, Cairo, between January 2016 and March 2019. The patients had a negative baseline and at least one other HCV antibody test. Hepatitis C virus antibody testing was done by antibody sandwich third-generation enzyme-linked immunosorbent assay. The hepatitis C virus infection incidence rate among HIV-infected patients was calculated using the person-time incidence rate. Two hundred and eighteen patients were finally included: 146 (31.7%) patients were excluded for having a positive baseline HCV Ab result and 96 patients were excluded for not having a follow-up HCV Ab test. Eighteen patients had HCV seroconversion (8.3%), achieving an incidence rate of 4.06 cases per 100 person-years (95% confidence interval: 3.87-4.24). Injection drug use (IDU) was the commonest risk factor among seroconverters, with an HCV incidence rate of 7.08 cases per 100 person-years. Injection drug use history was reported in 83.3% of the seroconverters and in only 47.2% of non-seroconverters; P = 0.005. Egyptian HIV-infected patients show a high incidence rate of HCV infection especially among those who have a history of IDU. Accordingly, attention should be paid for prevention, screening and timely treatment of HCV in patients infected with HIV. The demonstration of a high HCV infection incidence rate among HIV-infected patients and shows the need for screening and prevention in this population.

Doxycycline use and adverse pregnancy or neonatal outcomes: A descriptive study using the United States Food and Drug Administration Adverse Event Reporting System database.

Doxycycline is recommended for use in rickettsial diseases. The available evidence regarding its safety for rickettsial infection in pregnancy is limited. Our study aimed to describe the adverse events of doxycycline when used during pregnancy for any indication, in terms of adverse maternal and/or neonatal outcomes, using the United States Food and Drug Administration Adverse Event Reporting System (FAERS). We used the OpenVigil software for extracting the safety reports from the United States submitted to the FAERS from 2004 to 2021. We manually reviewed reports of doxycycline use resulting in adverse pregnancy outcomes or congenital anomalies to describe the patient and safety event characteristics. From 2004 to 2021, 59 individual case safety reports containing preferred terms indicative of drug exposure during pregnancy or drug-induced adverse fetal outcomes were identified in the FAERS database. Following deduplication and manual review, 20 relevant adverse event reports were obtained. Doxycycline was the suspect medication in 13/20 (65%) reports. The common adverse event terms reported were premature delivery/baby in 6 reports, spontaneous abortion in 6, intrauterine death in 2, and various congenital anomalies in the rest. Fifty percent of the safety reports contained other medications which could have potentially caused the outcome. The number of reported events in the FAERS database of adverse pregnancy/neonatal outcomes following doxycycline use is small, similar to the numbers reported from large cohort or surveillance studies. Given the presence of concomitant medications that could have contributed to the outcome, there does not seem to be a strong signal of harm, although this needs to be confirmed by surveillance studies.

Typhus Disease in Iran during the Qajar Period (1725 to 1925 AD); a Brief Historical Review.

Typhus is an acute febrile disease caused by a series of bacteria called Rickettsia that is transmitted by insects such as lice, fleas, and ticks. This disease has appeared several times in Iran and caused many casualties. There were some therapeutic measures taken by European physicians in Tehran and medical graduates of the Dar al-Fonun school or expatriates who had studied medical courses in Western countries, even though the taken steps were not enough. Due to the lack of sanitation and cleaning products after the outbreak of World War I in March 1917 and its synchronization with the swift outbreak of Typhus in 1918, heavy casualties followed. In this study, we first examine the prevalence of Typhus in the Qajar dynasty in Iran, and will then focus on the pathological importance of this disease history in Iran. After that, we will study the role of Typhus prevalence and World War I in the Persian famine, malnutrition, and food poverty. Moreover, we investigated the role that this great war had in strengthening the spread of this disease and its role in the death of many Iranian people.

SCRUB TYPHUS DISEASE OUTBREAK AT CHEURAL VILLAGE, LAWNGTLAI DISTRICT, MIZORAM, NORTH-EAST INDIA

Scrub typhus, which is one of the rickettsial diseases, is an acute, febrile illness in men caused by the pathogen, 18 a gram-negative bacterium Orientia tsutsugamushi from the bite of infected mite. Outbreaks of scrub typhus have been reported from various parts of North, South, and Eastern India. There was a report of two unfortunate death cases from Cheural village due to scrub typhus at Lawngtlai district hospital. While, multiple cases, having symptoms like scrub typhus illness were also reported by health officials of the residents of Cheural village, Lawngtlai District, Mizoram. Among the 242 person tested, 80 (33.05%) person were found reactive with Weil felix PROGEN OXK at 1:160 titre value. Maximum numbers of cases were observed among the working age group 20-60 years. Among the different occupational groups, farmers were the most affected as more than 90% of the villagers were involved in forest farming. The five captured rodents’ sera were also tested with Weil felix. All of the captured rodent sera were reactive with one or more antigen. Mites (chigger) were also collected from the rodent samples and the chigger index was found to be 19.2. This study indicated that scrub typhus and other rickettsial diseases were responsible for the outbreak. The extremely high chigger index with reactivity rate reactivity rate of Weil felix with sera of captured rodents strongly indicated the household transmission of scrub typhus and other rickettsial diseases in the outbreak village.

Rocky Mountain spotted fever, an underdiagnosed cause of headache

IntroductionRocky Mountain spotted fever is a tick-borne rickettsiosis. The main clinical signs and symptoms are fever, severe headache, rashes and myalgia. Endothelium tropism can lead to vasculitis, thrombosis, and hemorrhage. In addition, the disease can generate neurological impairment through meningoencephalitis, characterized by holocranial headache. It is considered difficult to diagnose and underreported because nonspecific signs and it is commonly confused with dengue. Objectives To analyze the epidemiology of spotted fever in São Paulo (state) between 2010 and 2020. MethodologyThe work is a descriptive cross-sectional study that statistically analyzes the cases of spotted fever in São Paulo between 2010 and 2020 through data obtained by the Information System of Notifiable Diseases (SINAN). The proportions of spotted fever cases were calculated according to: sex, age group, race/color, infection environment, confirmation criteria and evolution. The correlation coefficient between human development index (HDI) and that of the reporting city and mortality was estimated. The number of inhabitants and HDI were from the latest IBGE (Brazilian Institute of Geography and Statistics) census in 2010. ResultsThere are 869 cases were confirmed (representing 44% of the country's cases), of which 324 are from the metropolitan region of Campinas. The correlation coefficient between HDI and deaths is 0.06 and the average HDI of the cities is 0.79. (To see the complete abstract, please, check out the PDF).

Co-effects of global climatic dynamics and local climatic factors on scrub typhus in mainland China based on a nine-year time-frequency analysis

BackgroundScrub Typhus (ST) is a rickettsial disease caused by Orientia tsutsugamushi. The number of ST cases has been increasing in China during the past decades, which attracts great concerns of the public health. MethodsWe obtained monthly documented ST cases greater than 54 cases in 434 counties of China during 2012–2020. Spatiotemporal wavelet analysis was conducted to identify the ST clusters with similar pattern of the temporal variation and explore the association between ST variation and El Niño and La Niña events. Wavelet coherency analysis and partial wavelet coherency analysis was employed to further explore the co-effects of global and local climatic factors on ST. ResultsWavelet cluster analysis detected seven clusters in China, three of which are mainly distributed in Eastern China, while the other four clusters are located in the Southern China. Among the seven clusters, summer and autumn-winter peak of ST are the two main outbreak periods; while stable and fluctuated periodic feature of ST series was found at 12-month and 4-(or 6-) month according to the wavelet power spectra. Similarly, the three-character bands were also found in the associations between ST and El Niño and La Niña events, among which the 12-month period band showed weakest climate-ST association and the other two bands owned stronger association, indicating that the global climate dynamics may have short-term effects on the ST variations. Meanwhile, 12-month period band with strong association was found between the four local climatic factors (precipitation, pressure, relative humidity and temperature) and the ST variations. Further, partial wavelet coherency analysis suggested that global climatic dynamics dominate annual ST variations, while local climatic factors dominate the small periods. ConclusionThe ST variations are not directly attributable to the change in large-scale climate. The existence of these plausible climatic determinants stimulates the interests for more insights into the epidemiology of ST, which is important for devising prevention and early warning strategies.

Recent Threat of Scrub Typhus in India: A Narrative Review

Scrub typhus is an endemic illness transmitted by vectors and induced by bacteria. It is the most common and severe rickettsial disease. There are many more cases every year with a significant case fatality rate. Despite being a serious public health threat in India, it is uncertain how widespread and burdensome scrub typhus is. The scarcity of statistical information and pertinent health records on scrub typhus in the outbreak region demonstrates that there is still a significant knowledge gap about this neglected illness. Clinical manifestations of this illness include kidney failure, disability, and severe kidney failure. Undifferentiated symptoms, late diagnosis, and treatment failure are all responsible for deaths. Knowing about this disease is important from a public health point of view due to difficulties in specific diagnosis and a shortage of laboratory services in so many places. India is known to have scrub typhus cases, and doctors should be aware of this potentially dangerous but easily curable illness. The disease is highly difficult to identify clinically from other acute afebrile infections due to common symptoms and a paucity of the lesion in the Indian population. The mainstay of diagnosis is antibody-based serological testing. Within the first week of symptoms, scrub typhus can be diagnosed using molecular and serological tests. Our objective is to identify how severe scrub typhus is in India and to investigate the current epidemiology, etiology, complications, management, and treatment of the disease in both long-established endemic regions and new infection foci.

Survey on the Presence of Equine Tick-Borne Rickettsial Infections in Southcentral United States

Although ticks are known vectors of pathogens across a range of hosts, there is limited research on emerging tick-borne diseases of horses in the United States. Tick surveys from other regions suggest Rickettsia spp. and Ehrlichia spp. may be clinically relevant in horses. To better understand the transmission risk of these tick-borne rickettsial disease agents to horses, ticks were collected from horses in Oklahoma. Ticks for the current study (306 Amblyomma americanum, 20 Dermacentor albipictus, 19 D. variabilis, and 7 A. maculatum) were evaluated for Rickettsia spp. and Ehrlichia spp. using polymerase chain reaction and sequence analysis. Serum samples from infested and noninfested horses were evaluated for antibodies to R. rickettsii using indirect fluorescence antibody testing and Ehrlichia spp. and Anaplasma spp. using a commercial enzyme-linked immunoassay. Of the horses with tick infestations, 71.4% hosted at least one tick with a rickettsial agent detected. Rickettsia spp. were identified in 25.9% (91/352) of the ticks tested with R. amblyommatis (80.2%; 73/91) most often detected. Ehrlichia spp. were identified in 2.8% (10/352) of the ticks tested with E. ewingii most often identified. Serologic screening revealed no horses with antibodies to R. rickettsii or Anaplasma spp., but 29.6% of the examined horses had circulating antibodies to Ehrlichia spp. Together, these results demonstrate the presence of Rickettsia spp. and Ehrlichia spp. in equine ticks and evidence of past or current infection with Ehrlichia spp. in Oklahoma horses which strongly suggests there is a need to explore the relationship between these agents and equine health.

A PROSPECTIVE STUDY TO KNOW THE TRENDS OF SCRUB TYPHUS INFECTION DURING THE SEASONAL OUTBREAK AT A TERTIARY CARE HOSPITAL IN SOUTH RAJASTHAN, INDIA

Scrub typhus is a rickettsial disease caused by the organism Orientia tsutsugamushi. The overall mortality varies from 7% to 30%, next only to malaria among infectious diseases5. This prospective study was conducted with an aim to know the prevalence of the disease, sex ratio signicance and impact of seasons in the disease outcome in Rajsamand, Rajasthan. A total of 515 samples were received from different clinical departments at Ananta Institute of Medical Sciences and research center, Rajsamand from December 2020-December 2021, in which 88 samples were IgM Antibody reactive by Rapid card test and positivity is 16.7%. Scrub typhus infection was found comparatively more in female patients i.e., 48[55%] than in male patients 40 [45%]. The female to male ratio was 1.2:1. In the present study, majority of the patients 29 (32%) were from the age group of 31-45 yrs and about 19 (22%) were between 16-30 yrs. Maximum cases 31(35%) had occurred in the month of September followed by 27(31%) in October, 21(24%) in November and 4(5%), 3(3%), 2(2%) in the month of August, July and December 2021 respectively and not a single case reported in the month of December 2020 and from January 2021 to June 2021. So, scrub typhus should always be considered in the list of differential diagnosis of a young febrile female patient of this region mainly during the end of rainy season. This will help in proper diagnosis, timely and adequate treatment and avoidance of complications which are associated with high mortality

Pathology of Infectious Diseases

Part 1 General principles: changing spectrum of human infectious diseases host-parasite interplay role of pathology in diagnosis of infections types of tissue responses to infection microscopic detection of pathogenic organisms. Part 2 Viral infections: viral pathogenesis viral diseases of the digestive system viral skin rashes systemic and hematopoietic viral disorders adult immunodeficiency syndrome (AIDS) arboviral and zoonotic viral fevers viral encephalitis and myelitis viral myocarditis viral skin growths. Part 3 Chlamydial infections: chlamydial pathogenesis chlamydial diseases. Part 4 Rickettsial infections: rickettsial pathogenesis rickettsial diseases. Part 5 Mycoplasma infections: mycoplasma pathogenesis diseases caused by mycoplasmas. Part 6 Bacterial infections: bacterial pathogenesis diseases caused by pyogenic cocci diseases caused by common gram-negative bacteria bacterial diseases of childhood enteric bacterial diseases clostridial diseases zoonotic bacterial diseases rare gram-negative infections treponemal diseases mycobacterial diseases diseases caused by streptomycetales. Part 7 Fungal and algal infections: fungal pathogenesis superficial mycoses opportunistic mycoses endemic fungal diseases diseases caused by algae (protothecosis). Part 8 Protozoal infections: protozoal pathogenesis diseases caused by luminal protozoa diseases caused by bloodstream protozoa diseases caused by intracellular protozoa. Part 9 Helminthic infections: helminthic pathogenesis diseases caused by tissue nematodes filarial diseases diseases caused by cestodes diseases caused by trematodes. Part 10 Patients at special risk of infection: general risk categories residents and travellers in endemic areas pregnant women and neonates infants and elderly persons the poor, homeless, the addicted patients genetically predisposed immunosuppressed and leukopenic patients AIDS patients. Epilogue: the sience and art of infectious disease medicine.

Clinical Presentations of Covid-19 Infection in Pediatrics and Assessment of Cardiac Affection by Echocardiograph

Background: A series of published articles have reported the epidemiological and clinical characteristics of the hospitalized patients with COVID-19. Most patients reported in the literature were adults, and commonly presented with pneumonia and abnormal findings on chest CT. Elderly patients with comorbidities were more likely to exacerbate with severe and even fatal respiratory diseases such as acute respiratory distress syndrome (ARDS). The number of reported pediatric patients is limited and the clinical characteristics of pediatric COVID-19 was rarely reported. AIM: Studying of the clinical presentation of all pediatric patients admitted with clinical features suggestive or confirmed of Covid-19 infection during hospital stay. METHODOLGY: This is a cross sectional study, which included all the admitted patients meeting the inclusion criteria of suspected or confirmed COVID-19 infection admitted at Benha Fever Hospital during the period of study which will be 6 months. RESULTS: PICU Admission due to System Failure in 30%, mortality rate was 8.3%. Higher TLC, CRP, ferritin were associated with PICU Admission due to System Failure. Non survivors were significantly associated with higher TLC, ALC, CRP and lower oxygen saturation. Conclusion: COVID-19 might influence all body systems causing various clinical presentations varying from mild to life-threatening conditions.

Orientia tsutsugamushi: Diversity and Distribution in India: A Review

Scrub typhus is a disease caused by Orientia tsutsugamushi which is an obligate, intracellular gram-negative bacterium. It is endemic to a part of the world known as “tsutsugamushi triangle.” This extends from Japan, China, Taiwan, South Koria, Nepal, Pakistan, Papua New Guinea, Australian states of Queensland and Northern New South Wales. In India, it has been recognized for several years and the disease widely spread all over the country. The severity of scrub typhus disease has been reported to be strain dependent in humans. Orientia tsutsugamushi strains have been examined by various research tools. PCR amplification and sequencing of 56-kDa antigen gene is one of the most advanced tool in identifying O. tsutsugamushi strains and genotypes. In the present review, English-language literature for reports of Orientia tsutsugamushi genotype diversity and distribution in India was searched using PubMed and Google Scholar databases. The search terms scrub typhus or mite typhus or tropical typhus or tsutsugamushi disease or Orientia tsutsugamushi or Rickettsia tsutsugamushiwere used in combination with the term genotypes or strains or serotypes. The result of present review revealed limited Information related to genotype diversity and distribution in the country. Understanding a more detailed regional genetic diversity is required in region-specific vaccine development strategies andsero-diagnostics tools.

Molecular Detection and Genetic Characterization of Ehrlichia ruminantium Harbored by Amblyomma hebraeum Ticks of Domestic Ruminants in North West Province, South Africa.

Simple SummaryBont ticks (Genus Amblyomma) transmit Ehrlichia ruminantium (E. ruminantium), a pathogen that causes a rickettsial disease called heartwater in ruminants. Heartwater disease is devastating and causes financial loss in livestock farming in most parts of southern Africa. The E. ruminantium tends to have many variants; as a result, it is difficult to develop vaccines for controlling it. Knowledge of E. ruminantium variant occurrence in a particular area may assist in designing appropriate vaccination control strategies. Thus, this study investigated the E. ruminantium variants found in the Ngaka Modiri Molema District, North West Province, South Africa. Diversity of these E. ruminantium variants was determined by PCR and sequencing of DNA pools extracted from the tick vectors. Six different DNA variants of E. ruminantium were detected and compared well with those known to be virulent from other parts of South Africa and other countries. The type of variant commonly used for the massive vaccination was not detected in the study area.Ehrlichia ruminantium (E. ruminantium) is the causative agent of heartwater disease and it is mainly transmitted to livestock by Amblyomma hebraeum (A. hebraeum) tick in South Africa. This study investigated the occurrence of E. ruminantium and its genetic diversity in ticks within Ngaka Modiri Molema district of North West Province in South Africa. Genomic DNA was extracted from whole A. hebraeum ticks totaling 876 and resulted in a total of 292 pooled DNA samples. Firstly, conventional PCR was used to detect Ehrlichia spp. targeting the dsbA gene, followed by nested PCR targeting the Map1 gene performed on DNA pool samples that were positive from the first PCR. One hundred and six tick DNA pool samples were positive by dsbA gene PCR for the presence of Ehrlichia spp. with minimum infection rate (MIR) of 121, while 13/106 were positive by Map1 PCR with MIR of 15. Different E. ruminantium Map1 genotypes (NWUe1, NWUe2, NWUe3, NWUe5, and NWUe6) were detected from tick samples and were closely related to more than 13 gene sequences of E. ruminantium from the NCBI GenBank database. These findings suggest that there is a significant diversity of E. ruminantium infecting ticks in the study area.

Mannheimia haemolytica OmpH binds fibrinogen and fibronectin and participates in biofilm formation

Mannheimia haemolytica is the causal agent of the shipping fever in bovines and produces high economic losses worldwide. This bacterium possesses different virulence attributes to achieve a successful infection. One of the main virulence factors expressed by a pathogen is through adhesion molecules; however, the components participating in this process are not totally known. The present work identified a M. haemolytica 41 kDa outer membrane protein (Omp) that participates in bacterial adhesion. This protein showed 100% identity with the OmpH from M. haemolytica as determined by mass spectrometry and it interacts with sheep fibrinogen. The 41 kDa M. haemolytica OmpH interacts with bovine monocytes; a previous incubation of M. haemolytica with a rabbit hyperimmune serum against this Omp diminished 45% cell adhesion. The OmpH was recognized by serum from bovines affected by acute or chronic pneumonia, indicating its in vivo expression; moreover, it showed immune cross-reaction with the serum of rabbit infected with Pasteurella multocida. The OmpH is present in biofilms and previous incubation of M. haemolytca with rabbit serum against this protein diminished biofilm, indicating this protein's participation in biofilm formation. M. haemolytica OmpH is proposed as a relevant immunogen in bovine pneumonia protection.

Unraveling the epidemiological relationship between ticks and rickettsial infection in Africa

Tick-borne rickettsioses are emerging and re-emerging diseases of public health concern caused by over 30 species ofRickettsia. Ticks are obligate hematophagous arthropods with over 700 species of Ixodid ticks known worldwide. The escalating geographical dispersal of tick vectors and concomitant increase in the incidences of tick-borne diseases have fueled interest in the ecology of tick-borne pathogens. This review focuses on aspects of theRickettsiapathogen, including biology, taxonomy, phylogeny, genetic diversity, epidemiology of the disease, and the role of vertebrate host in the perpetuation of rickettsioses in Africa. Our review also highlights some of the species ofRickettsiathat are responsible for disease, the role of tick vectors (both hard and soft ticks) and the species ofRickettsiaassociated with diverse tick species across the continent. Additionally, this article emphasizes the evolutionary perspective of rickettsiae perpetuation and the possible role of amplifying vertebrate host and other small mammals, domestic animals and wildlife in the epidemiology ofRickettsiaspecies. We also specifically, discussed the role of avian population in the epidemiology of SFG rickettsiae. Furthermore, we highlighted tick-borne rickettsioses among travelers due to African tick-bite fever (ATBF) and the challenges to surveillance of rickettsial infection, and research on rickettsiology in Africa. Our review canvasses the need for more rickettsiologists of African origin based within the continent to further research towards understanding the biology, characterization, and species distribution, including the competent tick vectors involved in their transmission of rickettsiae across the continent in collaboration with established researchers in western countries. We further highlighted the need for proper funding to encourage research despite competing demands for resources across the various sectors. We finalize by discussing the similarities between rickettsial diseases around the world and which steps need to be taken to help foster our understanding on the eco-epidemiology of rickettsioses by bridging the gap between the growing epidemiological data and the molecular characterization ofRickettsiaspecies.

Incidence and Management of Rickettsial Infections among Febrile Patients Attending Inpatients and Outpatients Departments of a Tertiary Care Hospital: A Longitudinal study

Background: Rickettsial infection can occur by a number of obligate intracellular bacteria from the genus rickettsia which belongs to the Alphaproteobacteria. Rickettsial infection is the most frequent emerging and reemerging diseases. This infection has become an endemic disease worldwide. Aim: The aim of the study was to find the incidence of rickettsial disease in and management of rickettsial infections among febrile patients attending inpatients and outpatients department of a tertiary care hospital. Methods: This study was a retrospective cross-sectional study which was incidence and management of rickettsial infections among febrile patient of department of Medicine in Tairunnessa Memorial Medical College and Hospital, Gazipur, Bangladesh. The study was conducted during the period of January 2019- February 2022. The total sample size for this study was 86. Result: Most common age group affected was between 21-30 years accounting for 27(31.4%) of cases. Most of the patients 47(55%) were male and 39(45%) were female. 20(23.3%) patients were housewife and followed by 21(24.4%) were garment worker, 4(4.7%) were service holder and 30(34.9%) were from other occupation. All 86(100%) patients had fever and followed by generalized weakness in 39(45.3%), Headache in 24(27.9%), Cough and cold in 25(29%), Body ache in 9(10.5%), Vomiting in 8(9.3%), abdominal pain in 8(9.3%) and 18(20.9%) other complaints were also seen. CBC & ESR, Weil Felix test were done in all 86(100%) patients followed by Urine R/M/E in 54(62.8%), serum creatinine in 12(14%), USG of W/A was done in 11(12.8%), PBF in 5(5.8%), Urine C/S in 3(3.5%), S. Electrolytes in 2(2.3%) and other investigation was done in 9(10.5%) cases. Doxycycline was prescribed in all patients 86(100%) and followed by Esomeprazole to 68(79.06%), Linagliptin+Metformin to 18(20.9%), Glimipiride to 17(19.8%), Azithromycin and Domperidon to 8(9.3%), Montelukast and Pantoprazole to 7(8.1%), Rupatadine to 6(7%), Ondansetron .........