Fever Rickettsiae Research Articles

Detection of Bartonella sp. and a novel spotted fever group Rickettsia sp. in Neotropical fleas of wild rodents (Cricetidae) from Southern Brazil

The Neotropical region shows a great diversity of fleas, comprising more than 50 genera. The importance of the study of fleas is linked to their potential role as disease vectors. The aim of this study is to investigate the presence of Rickettsia spp. and Bartonella spp. in Neotropical fleas collected from wild rodents in Southern Brazil. From 350 rodents captured, 30 were parasitized by fleas. A total of 61 fleas belonging to two genera and six different species were collected (Craneopsylla minerva minerva, Polygenis occidentalis occidentalis, Polygenis platensis, Polygenis pradoi, Polygenis rimatus, and Polygenis roberti roberti). In 13 % of fleas of three different species (C. minerva, P. platensis, and P. pradoi) Rickettsia sp. DNA was found. Phylogenetic analysis of concatenated sequences of gltA, htrA, and ompA genes showed that Rickettsia sp. found in rodent fleas (referred as strain Taim) grouped together with Spotted Fever Group Rickettsia. In reference to Bartonella spp., five genotypes were identified in seven fleas of two species (C. minerva and P. platensis) and in five rodent spleens. Also, 207 frozen samples of wild rodents were screened for these pathogens: while none was positive for Rickettsia spp.; five rodent spleens were PCR-positive for Bartonella spp.. Herein, we show the detection of potential novel variants of Bartonella sp. and Rickettsia sp. in fleas collected of wild rodents from Southern Brazil. Further studies are needed to fully characterize these microorganisms, as well as to improve the knowledge on the potential role of Neotropical flea species as diseases vectors.

Molecular Detection of Spotted Fever Group Rickettsia (Rickettsiales: Rickettsiaceae) in Ticks of Iran.

Ticks are reservoir hosts of pathogenic Rickettsia in humans and domestic animals. Most pathogenic Rickettsia species belong to the spotted fever group (SFG). The present study aimed to determine the tick species infected with Rickettsia based on the genus-specific 23S ribosomal ribonucleic acid (rRNA), 16S rRNA, and citrate synthase (gltA) gene fragments. A total of 61 tick specimens were selected for molecular assay and 12 samples for sequencing. Phylogenetic analysis was conducted using neighbor-joining and Bayesian inference methods. Argas persicus, Haemaphysalis sulcata, Ha. inermis, and Hyalomma asiaticum were infected by spotted fever Rickettsia. The SFG is the main group of Rickettsia that can be detected in the three genera of ticks from Iran.

Rickettsial fever in tertiary care hospital in rural Bengaluru: Clinical profile and complications

Background: Rickettsial fever is a major health concern in different districts of Karnataka with serious complications, including morbidity and mortality, if diagnosed late. Objective: The objective of the present study was to know the clinical profile of Rickettsial fever in children. Materials and Methods: A descriptive study was conducted on all the laboratory-confirmed cases of Rickettsial fever in children admitted to a tertiary care hospital from December 2018 to November 2019. Results: Among 103 children studied, majority were males (66%) in the age group of 3–6 years. All the children presented with history of fever (100%) followed by decreased appetite (94%). The least common symptoms noticed were altered sensorium (1.9%), breathlessness (6.5%), and bleeding tendencies (6.5%). The most serious complications seen were shock (38.8%), hepatic dysfunction (7.7%), and myocarditis (3%). There were no deaths reported. The least common complication was renal failure. A single case had cranial nerve palsy with meningitis. Conclusion: It was concluded that male children in the age group of 3–6 years were more affected. The common symptoms observed were fever, decreased appetite, abdominal distension, and skin rash and the common complications were shock and myocarditis.

Tickbite-associated chronic pruritic lesions in an Afro-descendant population in the Cauca Department, Colombia. I. Clinical features and impact on health.

During a health survey in a remote area in southwest Colombia, it became apparent that a high percentage of the population suffered from chronic pruritus in association with high numbers of ticks and tickbites. To determine the clinical features and severity of tickbite-associated pruritus. At twotime points - 8weeks apart to account for seasonal effects - a cross-sectional study was conducted encompassing physical examination of the population, histological analysis of skin biopsies, and determining serum for antibodies against spotted fever (SFG) rickettsiae and typhus group (TG) rickettsiae. Ticks were identified using morphological criteria, and infection by rickettsiae was determined by PCR. About 94.5% of the population (95% CI 92-97%) showed clinical signs of a pruritic arthropod reaction and of chronic pruritus with lichenoid papules and hyper- and hypopigmented nodules on otherwise noninflamed skin. Pruritus markedly impaired the quality of life in terms of sleeping disturbances. No signs for other diseases were observed. Chronic pruritus appeared to be because of repeated tickbites and scratching, but not because of other dermatological or medical conditions. Antibodies against SFG and TG-rickettsiae were detected at 79.0% (95% CI 73-86) and 3.6% (95% CI 0.7-6), respectively. Ticks were identified as Amblyomma cajennense. Remarkably high exposure to tick bites caused an unusually high rate of acute and chronic pruritus and markedly impaired quality of life of the investigated rural community. This underlines the necessity of public health measures and surveillance of rickettsial disease.

Co-infections and COVID-19 in Children: An Observational Study

Acute illness iscaused by bacteria, viruses, and parasites.Co-infection is the simultaneous infectionof a host by multiple pathogens resulting in a delay in diagnosis and bad prognosis.Currentlycorona virus infection is a pandemic and global health concern. Coronavirus infection in children withconcomitant other infections is rarely reported in our country. This study was performed to find out the corona virus infectionassociated with recent illnesses to minimize morbidity and mortality. Study was done at Dr. M R Khan Shishu Hospital & ICH from April 2020 to June 2020. Patient with fever, rash, vomiting, diarrhea, cough, respiratory distress, dysuria, convulsion, jaundice and other symptoms; admitted in hospital were taken for this study. Diagnosis was made by clinical symptoms plus investigations accordingly and appropriate treatment was given for recent illnesses. During follow up these cases; there was persistence of symptoms and some other new features appeared. These arouse our suspicion that there might be associated with corona virus infection in this pandemic. Thirty cases were taken co-infection with COVID19.Age was found 4 months to 8 years.Male female ratio was 1.5: 1.Typhoid fever with COVID-1912(40%), Bacterial meningitis with COVID-196(20%), UTI with COVID-19 3(10%), Paratyphoid fever with COVID192(6.7%), Typhus/ Rickettsial fever withCOVID-19 2(6.7%),HAV infection withCOVID-192(6.7%),HEV infection withCOVID-19 1 (3.3%), Septic arthritis with COVID-191 (3.3%), Atypical pneumonia with COVID191 (3.3%) were found. RT-PCR was positive forCOVID-1930(100%), blood culture was positive for Salmonella Typhi 4(13.3%), Widal test was reactive (high rising titer) 8(26.7%), Latex agglutination test was positive for bacterial meningitis 6(20%), urine culture was positive for E.coli 3(10%), blood culture was positive for Salmonella Para typhi A 2(6.7%), Weil-Felix reaction was found (high rising titer) 2(6.7%), Anti HAV IgM was positive 2(6.7%), Anti HEV IgM was positive 1(3.3%), Blood culturewas positive for Septic arthritis 1(3.3%), blood culture was positive for Mycoplasma Pneumoniae 1(3.3%). This study showed that COVID-19 in Bangladeshi children was found associated with co-infections. So, coinfection with COVID-19 patients should be closely monitored and managed accordingly.

Status of Triple Antigen Test among Community Acquired Febrile Illness Patient attended at Tertiary Care Hospital, Bogura

Background: Bacterial etiologies of febrile illnesses have significantly become important due to high mortality and morbidity.
 Objective: This study aimed to identify the prevalence of rickettsial fever, brucellosis, and typhoid fever by triple antigen test.
 Methodology: This cross-sectional study was conducted at TMSS Medical College Bogura district in Bangladesh for 6 months. Febrile patients aged from 1 to 65 years of both sexes were recruited from the outpatient department of this Medical College Bogura. Blood sample were taken from all patients for antibody test by microscopic plate agglutination test according to manufacturer instruction.
 Results: A total of 140 patients were enrolled and 74/140 (52.86%) patients were positive by any of three antigens, among them female were 54/74 (72.97%), most common age group was 21 to 30 years which was 22/74(29.73%), TO titre was greater than TH titre, which was 24/36 (66.66%).
 Conclusion: The study has underscored the importance of febrile antigen detection for bacterial diseases including zoonosis such as ricketial fever, brucellosis and typhoid fever in febrile patient and thus reducing diagnostic dilemma of febrile diseases. However, further diagnostic tests for diagnosis of febrile illnesses also needed. This will be helpful for febrile patients to receive the correct diagnoses and facilitation of accurate and prompt treatment.
 Bangladesh Journal of Infectious Diseases 2020;7(1):18-21

Increased talin–vinculin spatial proximities in livers in response to spotted fever group rickettsial and Ebola virus infections

AbstractTalin and vinculin, both actin-cytoskeleton-related proteins, have been documented to participate in establishing bacterial infections, respectively, as the adapter protein to mediate cytoskeleton-driven dynamics of the plasma membrane. However, little is known regarding the potential role of the talin–vinculin complex during spotted fever group rickettsial and Ebola virus infections, two dreadful infectious diseases in humans. Many functional properties of proteins are determined by their participation in protein–protein complexes, in a temporal and/or spatial manner. To resolve the limitation of application in using mouse primary antibodies on archival, multiple formalin-fixed mouse tissue samples, which were collected from experiments requiring high biocontainment, we developed a practical strategic proximity ligation assay (PLA) capable of employing one primary antibody raised in mouse to probe talin–vinculin spatial proximal complex in mouse tissue. We observed an increase of talin–vinculin spatial proximities in the livers of spotted fever Rickettsiaaustralis or Ebola virus-infected mice when compared with mock mice. Furthermore, using EPAC1-knockout mice, we found that deletion of EPAC1 could suppress the formation of spatial proximal complex of talin–vinculin in rickettsial infections. In addition, we observed increased colocalization between spatial proximity of talin–vinculin and filamentous actin-specific phalloidin staining in single survival mouse from an ordinarily lethal dose of rickettsial or Ebola virus infection. These findings may help to delineate a fresh insight into the mechanisms underlying liver specific pathogenesis during infection with spotted fever rickettsia or Ebola virus in the mouse model.The authors observed an increase of talin-vinculin spatial proximities in the livers of spotted fever Rickettsiaaustralis or Ebola virus-infected mice when compared to mock mice. Furthermore, using EPAC1 knockout mice, they found that deletion of EPAC1 suppresses the formation of spatial proximal complex of talin-vinculin in rickettsial infections.

Сравнительная характеристика клинико-эпидемиологических особенностей Астра­ханской риккетсиозной и Крымской геморрагической лихорадок

Сравнительная характеристика клинико-эпидемиологических особенностей Астра­ханской риккетсиозной и Крымской геморрагической лихорадок

The role of Rhipicephalus sanguineus ticks parasitizing dogs in the spread of tick-borne rickettsial pathogens in the city of Sevastopol.

The occurrence of Mediterranean fever with periods of increase and decrease has been recorded in the Crimean peninsula. The city of Sevastopol and its vicinity are known endemic areas for this disease. Some of the most active agents in the spread of this rickettsiosis are feral and abandoned dogs. The aim of this study was to test ticks parasitizing dogs in Sevastopol for the presence of Rickettsia using molecular methods. The testing of ticks was carried out using real-time PCR and the ‘Real Best DNA Rickettsia species’ kit (AO ‘Vector-Best’) followed by sequence identification of the rickettsial DNA detected. The DNA marker for Rickettsia species (a conservative area of citrate synthase gene, gltA) was detected in 16 of 84 (19.1%) samples of Rhipicephalus sanguineus ticks tested. Larger fragments of gltA, ompA and sca4 were amplified and sequenced for 10 of 16 PCR-positive samples. Rickettsia DNA amplified from eight of the samples matched the sequence of Rickettsia conorii conorii Malish, the causative agent of Mediterranean fever. The sequences of Rickettsia DNA from two other ticks had the closest match to homologous fragments of Rickettsia massiliae, a pathogenic spotted fever rickettsia that was identified in the Crimean Peninsula for the first time as part of this study. The detection of two pathogenic species of Rickettsia in the studied ticks suggests the potential for two rickettsial diseases in the region and warrants further epidemiological and clinical studies.

Khảo sát tỷ lệ nhiễm Rickettsia và Orientia tsutsugamushi trên bệnh nhân sốt không rõ nguyên nhân tại Hà Giang

Rickettsial fever is one of a zoonotic disease which is caused by bacteria genus Rickettsia. The ectoparasites such as ticks, mites, fleas, lice... were demonstrated as the main transmited vectors through host reservoirs are rodents and small animals including mice, squirrels, mink... These is the main cause of Rickettsia infection in human. The prevalence of Rickettsia and Orientia tsutsugamushi in rodents and ectoparasites and patients in Vietnam were reported. However, the data still was not clearly and fully understanding. Ha Giang is one of the important provinces with complex mountainous terrain where there is a high risk of zoonotic diseases. The O. tsutsugamushi was detected in patients collected in Ha Giang province. In current paper, we describe the result for investigating the Rickettsia infection rate as well as the seroprevalence of scrub typhus, Rickettsia typhi and Rickettsia spotted fever group in fever of unknown origin patient collecting in Ha Giang province general Hospital. The ELISA result in 162 patients indicates that seroprevalence of Orientia tsutsugamushi, Rickettsia typhi, and Rickettsia spotted fever group are 33.33%, 8.02%, và 1.85%, respectively. The real-time PCR result shows that the positive rates of Orientia tsutsugamushi, Rickettsia typhi and Rickettsia spotted fever group are 24.69%, 5.63%, và 1.41%, respectively.

Clinicopathological profile of rickettsial fever in tertiary healthcare centre: a prospective case study

Background: Rickettsia are obligate intracellular proteobacteria spread by eukaryotic vectors like ticks, mites, fleas and lice. Rickettsial infections are generally incapacitating and difficult to diagnose; Case fatality rates up to 45 percent is seen in cases with multiple organ dysfunction. The disease continues to be under diagnosed and treated. Objective of this study was to study the clinicopathological profile and outcome of children admitted with rickettsial fever. To study the correlation between Rathi-Goodman-Aghai score and Weil-Felix test. To study the response of rickettsial fever to Doxycycline. Methods: This study is a prospective observational study conducted from December 2017 to April 2019 at a tertiary health care center in South India, involving patients admitted between 2 months to 18 years of age with a diagnosis of Rickettsial fever. Clinical data and investigations were collected and analysed. The response to doxycycline was recorded. Results: Total of 49 patients were enrolled in the study. Most common age group affected was between 1 to 5 years accounting for 32.7% of the cases. 78% of the patients hailed from rural background. Most common presentation being fever, present in 100% of the cases. 81.6% of patients had significant Rathi-Goodman-Aghai score of >14. Weil felix showed significant titres (1:80) in 97.9% out of which serology suggestive of scrub typhus was found in 79.6% patients. There was no statistical significance between rickettsial score and Weil-Felix test (p value= 0.736). 26.5% of the cases required respiratory support and 2% cases required dialysis. 10.2% cases succumbed and 89.8% cases improved.Conclusions: Rickettsial infection is re-emerging with propensity for life threatening complications. There is no statistical significant correlation between Rickettsial score and Weil Felix test. Early treatment has better outcome.

SAT-427 AKI IN TROPICS/PATIENT RETURNING FROM TROPICS -WHY EXPANDING OUR DIFFERENTIALS IS NEEDED!

CASE REPORT People living in tropics have some endemic risk factors specific to the demographic region they reside in. A variety of causes are prevalent - including Malaria, Dengue Hemorrhagic Fever, Infectious Diarrhea, Leptospirosis, Snake Envenomation, and Scrub Typhus. We describe a case of Scrub Typhus with AKI. This particular case is interesting as it was from a cosmopolitan city, away from hilly areas where this rickettsial fever is more common. World Health Organisation (WHO) has recently warned about the potential of Scrub Typhus to cause widespread disease in tropics, deviating from the natural restriction to hilly areas to occurring in cities or towns. Scrub typhus is an important disease - frequently neglected. The annual estimate of cases is 1 million, while the population at risk, at 2 Billion is even huge, with the Tsutsugamoshi triangle extending from Japan in the east to Pakistan in the west and China to the north and Australia to the south. A 21-year-old male had presented with an 8-day history of low-grade fever, diarrhea, and oliguria. On evaluation, the patient was found to be febrile, dehydrated and in hypotension. He had icterus and tender inguinal lymphadenopathy. The patient remained anuric after rehydration despite recovering from hypotension. The patient received Hemodialysis as required. Patient was thoroughly investigated for etiology. Labs are depicted in tables uploaded together as pictures. Chest Radiograph : Normal Ultrasound of Abdomen and Pelvis:Mild Splenomegaly, Mild Ascites, Multiple Sub Centimetric Aorto-Iliac Lymph nodes. Minimal Bilateral Pleural Effusions. DIAGNOSIS: ENDEMIC ZOONOSIS SCRUB TYPHUS - WITH MULTI SYSTEM INVOLVEMENT- AKI, HEPATITIS, BICYTOPENIA. CONCLUSIONS: Scrub Typhus is thought to be a rare, endemic cause of AKI- prevalent in hilly and mountainous areas. The current case report points to an atypical presentation of the disease in a young male who had recently visited an urban garden, in the city of Hyderabad in southern India. This is due to the rapid expansion of cities extending into surrounding forest areas. The Eschar over skin which is pathognomonic- is absent in our case which had made the diagnosis difficult. Also, the presence of eschar is highly variable, is strain-specific and the dark complexion of skin makes the identification of eschar difficult. The discovery of new vectors of the pathogen, by Tilak et al (Schoengastiella ligula -northeast India) in India and Lee et al (Euschoengastia koreaensis in South Korea), marks an important breakthrough in the understanding of the epidemiology of the disease. REFERENCES: 1. Incidence, risk factors and clinical outcomes of acute kidney injury associated with scrub typhus: a retrospective study of 510 consecutive patients in South Korea (2001–2013) Hwang K, et al. BMJ Open 2017;7:e013882. doi:10.1136/bmjopen-2016-013882

Outbreak of acute undifferentiated febrile illness in Kathmandu, Nepal: clinical and epidemiological investigation

BackgroundOutbreaks of acute undifferentiated febrile illness (AUFI) are common in Nepal, but the exact etiology or risk factors for them often go unrecognized. Diseases like influenza, enteric fever and rickettsial fevers account for majority of such outbreaks. Optimal diagnostic tests to inform treatment decisions are not available at the point-of-care. A proper epidemiological and clinical characterization of such outbreaks is important for appropriate treatment and control efforts.MethodsAn investigation was initiated as a response to increased presentation of patients at Patan Hospital from Chalnakhel locality in Dakchinkali municipality, Kathmandu with AUFI from June 10 to July 1, 2016. Focused group discussion with local inhabitants and the epidemiological curve of febrile patients at local primary health care centre confirmed the outbreak. The household-survey was conducted in the area with questionnaire administered on patients to characterize their illnesses and their medical records were reviewed. A different set of questionnaire was administered on the patients and controls to investigate the association with common risk factors. Water samples were collected and analyzed microbiologically.ResultsEighty one patients from 137 households suffered from febrile illness within 6 weeks window before the investigation. All the 67 sampled patients with acute fever had a generalized illness without a discernible focus of infection. Only 38% of the patients had received a clinical diagnosis while the rest were treated empirically without a diagnosis. Three patients had blood culture confirmed enteric fever. Forty-two (63%) patients had been administered antibiotics, most commonly, ofloxacin, cefixime or azithromycin with a mean fever clearance time of 4 days. There was no definite association between several risk factors and fever. Fecal contamination was noted in tap water samples.ConclusionBased on the pattern of illness, this outbreak was most likely a mixture of self-limiting viral infections and enteric fever. This study shows that even in the absence of a confirmed diagnosis, a detailed characterization of the illness at presentation and the recovery course can suggest the diagnosis and help in formulating appropriate recommendation for treatment and control.

Serosurvey on rickettsiae of the spotted fever group and Rickettsia bellii among dogs in the state of Goiás, Brazil.

The purpose of this study was to do a serological survey on three rickettsial species: Rickettsia rickettsii and Rickettsia parkeri, two species of the spotted fever group (SFG) that are considered to be great importance for public health; and Rickettsia bellii, a species of unknown pathogenicity that infects a variety of human-biting ticks. Serum samples from 273 dogs were tested using the indirect immunofluorescence assay (IFA). A total of 52 samples (19.04%) were seropositive for at least one of the three Rickettsia spp. antigens. Thirty-eight (73.07%), twelve (23.07%) and one (1.92%) of these dogs showed homologous reactions to R. bellii, R. rickettsii and R. parkeri, respectively. Our results showed that the seroprevalence of Rickettsia spp. was relatively low. However, the positive serological tests indicated that these dogs had become infected by these agents at some point in their lives. Lastly, our study adds to the previous knowledge on the epidemiology of rickettsiosis in the state of Goiás by doing the first record of detection of anti-R. rickettsii, R. parkeri and R. bellii antibodies by IFA among dogs, thus indicating that these agents may be circulating in the dog population analyzed.

A study of the comparative clinical profiles of scrub typhus, spotted fever group, and typhus group rickettsial infections at a rural tertiary care hospital

Background: The rickettsioses represent a major cause of acute febrile illnesses worldwide. The greatest challenge lies in diagnosing rickettsioses in a timely manner early in the course, when antibiotic use is most effective. In most cases clinical suspicion together with a positive serology is employed to make the diagnosis of rickettsiosis. Aim and Objective: To study the syndromic differences, if any, amongst the three groups of rickettsial infections present in India. Methods: This was a cross-sectional observational study that evaluated a total of 172 cases of rickettsial fever out of a pool of 778 cases of acute febrile illness between the June 2017 and March 2019. A careful search for eschar, lymphadenopathy and rashes was made. Weil Felix test was done after exclusion of other infections like malaria, dengue, enteric fever. To avoid the possibility of false positives, a single titer dilution >1:320 was considered positive for rickettsioses. Results: Fever was seen in all cases. Myalgia (81·5%), headache (72·8%), and splenomegaly (51·9%) were common in scrub typhus. Eschar was seen in only 8·4% cases. Spotted fever group presented with fever of shorter duration of less than seven days (64·7%), and gastrointestinal symptoms like vomiting (74·5%) and diarrhea (13·7%) were predominantly seen. Spotted fever group had macular rash as predominant sign. Typhus group presented with fever of longer duration of more than fourteen days (50%) and respiratory symptoms like cough (65%). Hepatomegaly was present in 35% and lymphadenopathy in 7·5%. Conclusion: Rrickettsial infections remain a diagnostic challenge in resource-poor settings. Therefore, it is important to recognize the clinical features promptly, include rickettsioses in the differential diagnoses, and consider early initiation of appropriate treatment.

Clinical profile of Rickettsial fever in children in a government tertiary care institute in north Karnataka

Clinical profile of Rickettsial fever in children in a government tertiary care institute in north Karnataka

Evolution, purification, and characterization of RC0497: a peptidoglycan amidase from the prototypical spotted fever species Rickettsia conorii.

Rickettsial species have independently lost several genes owing to reductive evolution while retaining those predominantly implicated in virulence, survival, and biosynthetic pathways. In this study, we have identified a previously uncharacterized Rickettsia conorii gene RC0497 as an N-acetylmuramoyl-L-alanine amidase constitutively expressed during infection of cultured human microvascular endothelial cells at the levels of both mRNA transcript and encoded protein. A homology-based search of rickettsial genomes reveals that RC0497 homologs, containing amidase_2 family and peptidoglycan binding domains, are highly conserved among the spotted fever group (SFG) rickettsiae. The recombinant RC0497 protein exhibits α-helix secondary structure, undergoes a conformational change in the presence of zinc, and exists as a dimer at higher concentrations. We have further ascertained the enzymatic activity of RC0497 via demonstration of its ability to hydrolyze Escherichia coli peptidoglycan. Confocal microscopy on E. coli expressing RC0497 and transmission immunoelectron microscopy of R. conorii revealed its localization predominantly to the cell wall, septal regions of replicating bacteria, and the membrane of vesicles pinching off the cell wall. In summary, we have identified and functionally characterized RC0497 as a peptidoglycan hydrolase unique to spotted fever rickettsiae, which may potentially serve as a novel moonlighting protein capable of performing multiple functions during host-pathogen interactions.

Detection of Crimean-Congo Haemorrhagic Fever cases in a severe undifferentiated febrile illness outbreak in the Federal Republic of Sudan: A retrospective epidemiological and diagnostic cohort study.

BackgroundUndifferentiated febrile illness (UFI) is one of the most common reasons for people seeking healthcare in low-income countries. While illness and death due to specific infections such as malaria are often well-quantified, others are frequently uncounted and their impact underappreciated. A number of high consequence infectious diseases, including Ebola virus, are endemic or epidemic in the Federal Republic of Sudan which has experienced at least 12 UFI outbreaks, frequently associated with haemorrhage and high case fatality rates (CFR), since 2012. One of these occurred in Darfur in 2015/2016 with 594 cases and 108 deaths (CFR 18.2%). The aetiology of these outbreaks remains unknown.Methodology/Principal findingsWe report a retrospective cohort study of the 2015/2016 Darfur outbreak, using a subset of 65 of 263 outbreak samples received by the National Public Health Laboratory which met selection criteria of sufficient sample volume and epidemiological data. Clinical features included fever (95.8%), bleeding (95.7%), headache (51.6%) and arthralgia (42.2%). No epidemiological patterns indicative of person-to-person transmission or health-worker cases were reported. Samples were tested at the Public Health England Rare and Imported Pathogens Laboratory using a bespoke panel of likely pathogens including haemorrhagic fever viruses, arboviruses and Rickettsia, Leptospira and Borrelia spp. Seven (11%) were positive for Crimean-Congo haemorrhagic fever virus (CCHFV) by real-time reverse transcription PCR. The remaining samples tested negative on all assays.Conclusions/SignificanceCCHFV is an important cause of fever and haemorrhage in Darfur, but not the sole major source of UFI outbreaks in Sudan. Prospective studies are needed to explore other aetiologies, including novel pathogens. The presence of CCHFV has critical infection, prevention and control as well as clinical implications for future response. Our study reinforces the need to boost surveillance, lab and investigative capacity to underpin effective response, and for local and international health security.

In vitro evaluation of minimum inhibitory concentration of several antibacterial agents against Rickettsia japonica using a plaque reduction assay system

The study was conducted to determine the minimum inhibitory concentrations (MICs) of several antibacterial agents against Rickettsia japonica, which causes Japanese spotted fever. A plaque reduction assay as an in vitro culture method was conducted to determine the MICs of antibacterial agents (4 types of tetracyclines: tetracycline, doxycycline, minocycline, and tigecycline; 3 types of quinolones: ciprofloxacin, ofloxacin, and levofloxacin; and 2 types of macrolides: azithromycin and clarythromycin) against R. japonica. R. japonica was sensitive to the antibacterial agents tested with MICs similar to those against other spotted fever rickettsia determined in previously described plaque reduction assays.

A relapsing fever Borrelia and spotted fever Rickettsia in ticks from an Andean valley, central Chile.

In humans, emerging infectious diseases are mostly zoonoses with ticks playing an important role as vectors. Tick-borne relapsing fever Borrelia and spotted fever Rickettsia occur in endemic foci along tropical and subtropical regions of the globe. However, both are widely neglected etiologic agents. In this study, we performed molecular analyses in order to assess the presence of Borrelia and Rickettsia DNA in ticks infesting small-mammals within a National Reserve located in the Andes Mountains, central Chile. While hard ticks were negative for the presence of both agents, sequences of four rickettsial (gltA, htrA, ompA, ompB) and two borrelial (16S rRNA and flaB) genes were obtained from larvae of an Ornithodoros sp. morphologically related with Ornithodoros atacamensis. Phylogenetic analyses indicated that the detected Borrelia and Rickettsia spp. belong to the relapsing fever and spotted fever groups, respectively. Moreover, the agents formed monophyletic clades with Rickettsia amblyommatis and "Candidatus Borrelia johnsonii." As positive ticks parasitize rodents within a highly visited National Reserve where outdoor activities are of common practice, the risk for human parasitism should not be discarded.