Vector borne and zoonotic diseases最新文献

Background: In urban Thailand, arboviral infections dominate diagnoses of acute undifferentiated fevers (AUFs) owing to their well-defined epidemiology and characteristic clinical presentations. However, rickettsial diseases, also endemic in this setting, remain under-recognized owing to challenges in early detection. Objective: This study aimed to identify potential rickettsial infections among patients with AUF in Bangkok and vicinity utilizing leftover nucleic acid extracted from serum samples from patients initially suspected of but negative for arbovirus infections. Materials and Methods: A total of 609 nucleic acid samples were screened for rickettsial bacteria using real-time PCR, targeting the 17-kDa common antigen gene of Rickettsia spp. and the 47-kDa gene of Orientia tsutsugamushi. Results: Nine samples were positive for Rickettsia spp. and two were positive for O. tsutsugamushi. DNA sequence and phylogenetic analyses based on partial 17-kDa antigen and citrate synthase (gltA) genes identified the Rickettsia-positive samples as R. typhi in eight cases and R. felis in one case. Analysis of the 56-kDa type-specific antigen gene identified the two O. tsutsugamushi isolates as Gilliam-related genotypes. Although rickettsial diseases typically present with mild symptoms, two patients with R. typhi infection (murine typhus) developed respiratory distress syndrome, highlighting the potential for rare but serious complications. Conclusion: This study underscores the critical importance of differential diagnosis and prompt, effective intervention to prevent complications in suspected cases.

Background: Tick-borne relapsing fever (TBRF) caused by Borrelia persica is an endemic disease in Israel and highly prevalent in military personnel. Prevention among the Israel Defense Force soldiers is based on increased awareness mainly in hyperendemic areas and selective postexposure prophylaxis with doxycycline. In this study, we report the presence of a suspected outbreak of TBRF in four soldiers who spent 30 h inside a deserted bunker. Materials and Methods: Clinical data on TBRF suspected cases were retrieved from clinical records, soft ticks were collected using carbon dioxide (CO₂) traps and their DNA was extracted and analysed by PCR and nucleotide sequencing. Environmental conditions such as relative humidity, air temperature, wind speed, and type of soil, as well as presence or absence of animal traces inside the bunkers were documented. Results: TBRF-like clinical symptoms in the patients included: tick bite scars, fever (37.5-39.2°C), rash, tachycardia, hypotension, myalgia, cough, headache, cervical lymphadenopathy and nausea. Microscopic search for B. persica in blood smears was performed in three patients and was negative. Out of the 255 Ornithodoros tholozani ticks collected from the bunker, 198 were analyzed and 2 (1%) were infected with B. persica. To determine if tick infestation in military bunkers is a common phenomenon, we surveyed nine additional military bunkers located in four different geographical areas for the presence of soft ticks. Only one additional bunker was infested with two O. tholozani ticks, both negative for B. persica. Presence of earth that probably helped sustain a relatively big tick population was observed on the floor in the highly infested bunker. Environmental treatment with lambda-cyhalothrin at 9.7% was performed and showed efficacy with no ticks recovered in the infested bunker 124 days after intervention. Conclusion: This study shows that military bunkers may harbor soft ticks infected with B. persica and entrance into bunkers should be considered as a risk for acquiring this infection like entrance into natural caves and archeological ruins.

Background: Lyme disease, caused by infection with Borrelia burgdorferi, is the most common vector-borne disease in the United States. The standard two-tier testing (STTT) algorithm suffers from low sensitivity, misinterpretation, and long turnaround time, preventing timely detection and treatment. To address these challenges, we hypothesized that the canine point-of-care (PoC) SNAP 4Dx Plus test used to detect Borrelia burgdorferi antibodies could be employed for human diagnosis. Materials and Methods: The SNAP 4Dx Plus testing was conducted in accordance with the manufacturer's instructions, with results read by manual inspection. All analyses were conducted using R version 4.3.1, and agreement between the PoC assay and the STTT was assessed using kappa statistics with GraphPad software. Results: We included 102 previously-tested human serum samples, of which 19 samples (18.6%) were STTT positive. Compared to the STTT, the SNAP 4Dx Plus test demonstrated a low sensitivity of 0.16 (95% CI 0.03 to 0.40). Conclusion: Overall, our results do not support the use of the SNAP 4Dx Plus LD assay for the diagnosis of human Lyme disease. Differences in antibody concentrations between human and canine samples may partly explain our findings.

Background: The rickettsioses, except for typhus fever and scrub typhus (ST), were not really recognized as distinct clinical entities until the early 20th century. Only when specific rickettsial serologic testing was introduced in the 1940s could the precise etiologies of various rickettsial diseases (RDs) be determined with certainty. Although ST is a well- recognized zoonotic disease entity, but non-scrub typhus rickettsial infection like spotted fever group and typhus group are not well studied in India and are still underestimated. Methods: We report cases who had shown seropositivity of spotted fever and typhus fever RD in IgM and IgG ELISA whose samples were referred from various hospitals of Delhi/National Capital Region in which clinicians had strong suspicion of rickettsiosis other than ST or Weil-Felix test found positive for any of the OX2, 19, and K antigens. Results: We reported 18 cases of SFG and TGRD with mostly cases presented with fever followed by hepato-intestinal symptoms. Conclusion: The vast variability and nonspecific presentation of rickettsiosis in spotted and typhus fever at times have often made it difficult to diagnose clinically. Prompt antibiotic therapy shortens the course of the disease, lowers the risk of complications, and in turn, reduces morbidity and mortality owing to RDs. There is a distinct need for physicians and health care workers at all levels of care in India to be aware of the clinical features, available diagnostic tests and their interpretation, and the therapy for these infections.

Background: Most of the rickettsioses are transmitted by ticks, and often overlooked by the medical profession, but are clinically important as they cause major human diseases. Recent studies have shown the existence of some rickettsial species in Iran, but very little information is available about the status of rickettsial epidemiology and ecology. This study investigated the presence of Rickettsia spp. in ticks and ruminants in western of Iran by molecular methods. Materials and Methods: 250 blood samples were collected from sheep and goats, as well as 244 ticks were collected opportunistically from ruminants in the Kurdistan province. The collected samples were tested using a real-time quantitative PCR (qPCR) assay targeting the Rickettsia 16SrRNA gene. Rickettsia spp. positive by the qPCR were further amplified by conventional PCR of the gltA and OmpA genes. These ampliqons were further analyzed by sequencing. Results: The ticks species collected in this study included Rhipicephalus sanguineus, Rh. turanicus, Haemaphysalis concinna, and Dermacentor marginatus. In total, DNA of Rickettsia spp. was detected in 131 collected ticks (53.7%). Of the positives, Rickettsia slovaca (59.2%) and Ri. hoogstraalii (16.3%) were the most common species identified followed by Ri. raoultii, Ri. massiliae, Ri. sibirica, and Ri. conorii subsp. israelensis. In contrast, there were no positives observed in the blood samples collected from ruminants. Conclusion: The results indicate the presence of rickettsial species in ticks. The detection of these pathogens is significant because they cause clinical disease in humans. The results support the notion that the Iranian public health system needs to be more aware of these diseases.

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic tick-borne disease, caused by an arbovirus of the genus Orthonairovirus and the family Nairoviridae. Crimean-Congo hemorrhagic fever virus (CCHFV) is widespread in several regions of the world. While the virus is not pathogenic to all susceptible livestock and wild mammals, it can lead to severe hemorrhagic fever in humans. In this review, we compiled published data on CCHFV infections in humans, animals, and ticks in Tunisia. Based on that, we discussed the epidemiology and the distribution patterns of CCHFV infections highlighting the risk factors for this virus in the country. CCHF infection prevalence in humans was estimated to 2.76% (5/181) and 5% (2/38) in Tunisian febrile patients and Tunisian slaughterhouse workers, respectively. Concurrently, seroprevalence in domestic ungulates (sheep, goats, cattle, and dromedaries) ranged from zero to 89.7%, and only one Hyalomma impeltatum tick specimen collected from dromedaries in southern Tunisian was positive for CCHFV by reverse transcriptase-polymerase chain reaction (0.6%; 1/165). As Tunisian studies on CCHFV are geographically scattered and limited due to very small sample sizes, further studies are needed to improve the knowledge on the epidemiology of CCHF in Tunisia.

Retrospective serological and case diagnostic data of endemic bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) provide evidence of viral transmission among livestock and wildlife from 2016 in Kansas and Nebraska. Serological testing of mature cattle in nine distinct regional zones of Kansas revealed 76% to 100% had detectable antibodies to BTV and/or EHDV. Specimens tested in the Kansas Veterinary Diagnostic Laboratory (55 submissions) were 51% test positive for antibodies to BTV and/or EHDV. Specimens tested in the Nebraska Veterinary Diagnostic Center (283 submissions) were 25% test positive for antibodies to BTV and/or EHDV. Low disease incidence in white-tailed deer and other susceptible wild ungulates was observed during 2016. However, there were no confirmed reports of disease in livestock in either state. The reasons for emergence of significant clinical disease in livestock and wildlife populations remain undefined.

Introduction: Brucellosis, which is among the endemic regions of Turkey, is a common zoonotic disease. The gold standard in diagnosing brucellosis is culture. We aimed to compare demographic characteristics, risk factors, and clinical and laboratory variables between cases with culture positivity and undetected in culture. Materials and Methods: This single-center study was conducted between January 2007 and April 2022. Clinical and laboratory data of patients with brucella growth in blood culture and patients without growth were compared. Results: A total of 150 patients were included in the study. The median age was 10 (1-18 years). Of the patients, 66 (44%) were female and 84 (56%) were male. Forty (26.7%) of the patients were bacteremic and 110 (73.3%) were nonbacteremic. In the bacteremic group, white blood cell count, platelet, and hemoglobin counts were lower, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values were higher. In clinical evaluation, fever, hepatomegaly, splenomegaly, and abdominal pain were more common in the bacteremic group. Conclusion: The distinction between bacteremic and nonbacteremic brucellosis can be predicted using laboratory values such as white blood cells, hemoglobin counts, platelet, ALT, and AST, and clinical findings such as fever, abdominal pain, hepatomegaly, and splenomegaly.

Background: The potential molluscicidal extracts, obtained from indigenous plants Cannabis sativa, Acacia nilotica, and Tinospora cordifolia, were tested for toxicity against freshwater pulmonate snail Lymnaea acuminata, an intermediate host of Fasciola hepatica. The organic extracts had a significant effect on young snails. Materials and Methods: All organic extracts and column-purified fractions gave median lethal concentrations (19-100.05 mg/L; 24 h) that fell well within the threshold level of 100 mg/L, set for a potential molluscicide by the World Health Organization. Results: The toxicity of T. cordifolia stem acetone extract (96 h LC₅₀: 16.08 mg/L) was more pronounced compared with C. sativa leaf ethanol extract (96 h LC₅₀: 16.32 mg/L) and A. nilotica leaf ethanol extract (96 h LC₅₀: 24.78 mg/L). β-caryophyllene, gallic acid, and berberine were characterized and identified as active molluscicidal components. Co-migration of β-caryophyllene (retardation factor [Rf] 0.95), gallic acid (Rf 0.30), and berberine (Rf 0.23) with column-purified parts of Cannabis sativa, Acacia nilotica, and Tinospora cordifolia on thin-layer chromatography demonstrates same Rf value, that is, 0.95, 0.30, and 0.23, respectively. Conclusion: This study indicates that these extracts thus represent potential plant-derived molluscicides that are worthy of further investigations.

Background: Ehrlichia canis has been the main hemopathogen affecting domestic dogs in Brazil. Even though tick-infested dogs may lead to household infestation and predispose human exposure and public health concern, no comprehensive study has surveyed humans, dogs, and environmental ticks altogether. Materials and Methods: Accordingly, the present study aimed to assess tick-infested households, identify tick species, perform serological (immunofluorescence assay) and molecular (PCR and q-PCR) detection of Ehrlichia in ticks, in the eighth biggest metropolitan area of Brazil. Results: Between 2007 and 2020, 233/5973 (3.9%) out of all complaints were from tick-infested households of 200 different addresses. Overall, 370/552 (67.0%) ticks were collected and identified as adult and 182/552 (33.0%) as immature forms of Rhipicephalus sanguineus s.l. complex; a single tick from one owner, a female tick of Amblyomma sculptum; and 395 ticks from dogs, 319/395 (80.8%) adult and 72/395 (18.2%) immature forms of Rhipicephalus spp., and 4/395 (1.01%) female Amblyomma aureolatum. Overall, 2/135 (1.5%) owners and 13/136 (9.6%) dogs were seropositive for E. canis. The DNA of Anaplasmataceae family was molecularly detected in 16/50 (32.0%) R. sanguineus s.l. As expected, the number of monthly tick infestation complaints were directly associated, and mean (p = 0.01), maximum (p = 0.011), and minimum (p = 0.008) temperature were statistically significant and had a low positive correlation (0.24, 0.23, and 0.24, respectively). In addition, complaints were highly associated to all socioeconomic variables (p < 0.001), with the exception of the presence of vacant lots. Conclusions: Despite low samplings and human negative results, areas with low-income with adequate temperature and urban agglomerations have been shown to be associated risks for tick infestations, predisposing tick-borne diseases. In conclusion, monitoring should always be conducted in such areas, including One Health approach with serosurvey of owners and dogs, along with identification and molecular screening of ticks.