Vector borne and zoonotic diseases最新文献

Background: Soft ticks (Family: Argasidae) are vectors of relapsing fever Borrelia in the United States and are potential vectors of African swine fever virus, a pathogen that could have a devastating effect on the U.S. swine industry if introduced to the U.S. mainland. Much of the tick-borne disease research in the U.S. focuses on hard ticks, and less is known about the ecology of soft ticks. Some soft tick species found in the southern U.S. have a wide host range and may feed on cattle, swine, native and exotic ungulates, small mammals, reptiles, and humans. Because the feeding habit of most soft tick species involves taking short, repeated blood meals that may include multiple host species, pathogen transmission among hosts is a concern both for human and animal health. Materials and Methods: Sampling was carried out at four locations in south Texas using dry ice traps placed in or near animal burrows and other sheltering cracks and crevasses that may provide refuge for soft ticks. Collected ticks were identified and subsequently screened for Rickettsia and Borrelia species and for host bloodmeal detection using conventional polymerase chain reaction and Sanger sequencing for pathogen and host species identification. Results: In total, 256 ticks of two Ornithodorinae species were screened. Borrelia species were identified in three samples. Bloodmeal detections were made in 22 tick specimens, representing eight vertebrate host species. Conclusions: Results demonstrate that the soft tick species detected herein feed on a range of wildlife hosts in south Texas and are associated with agents of human disease.

The emergence and spread of infectious diseases, particularly zoonotic diseases originating from wildlife, pose significant threats to global health and economy. This review examines the pivotal role of ticks as vectors in transmitting pathogens to humans, livestock, and wildlife and the use of molecular techniques in their identification. Tick infestations result in economic losses through reduced animal productivity, anemia, and quality deterioration of hides. Furthermore, ticks serve as reservoirs for a wide range of pathogens including viruses, bacteria, fungi, protozoa, and nematodes, contributing to the transmission of diseases such as Crimean-Congo hemorrhagic fever, tick-borne encephalitis, and African swine fever among others. The interface between wildlife, livestock, and humans facilitates the transmission of zoonotic pathogens, exacerbated by nomadic and pastoralist lifestyles that promote interactions between wildlife and domestic animals. This movement of animals across landscapes enhances the dispersion of tick vectors, increasing the risk of pathogen exposure for diverse populations. Historically, tick identification in sub-Saharan Africa has relied on morphological characteristics despite limitations such as species overlap and variability. Molecular techniques offer a more precise means of species identification, providing critical data for effective tick and pathogen management strategies. Integrating molecular approaches into tick research enhances our understanding of tick diversity, distribution patterns, and pathogen dynamics. This knowledge is essential for developing targeted interventions to mitigate the impact of tick-borne diseases on public and veterinary health worldwide.

Introduction: Lyme disease is the most common vector-borne disease in the United States and Canada. The primary vector for the causative agent of Lyme disease, Borrelia burgdorferi, in the Pacific Northwest is the western blacklegged tick, Ixodes pacificus. Materials and Methods: Using active tick surveillance data from British Columbia, Canada, and Washington State, USA, habitat suitability models using MaxEnt (maximum entropy) were developed for I. pacificus to predict its current and mid-century geographic distributions. Passive surveillance data both from BC and WA were also visualized. Results: According to the constructed models, the number of frost-free days during the winter is the most relevant predictor of its habitat suitability, followed by summer climate moisture, ecoregion, and mean minimum fall temperature. The ensemble geographic distribution map predicts that the coastal regions and inland valleys of British Columbia and the Puget Lowlands of Washington State provide the most suitable habitats for I. pacificus. The density map of ticks submitted from passive surveillance data was overlaid on the current distribution map and demonstrates the correlation between numbers of submissions and habitat suitability. Mid-century projections, based on current climate change predictions, indicate a range expansion, especially of low and moderate suitability, from current distribution. Regarding Lyme disease risk, I. pacificus identified from both active and passive surveillance and tested positive for B. burgdorferi were found to be in areas of moderate to very high suitability for I. pacificus. Conclusion: According to developed models, the total suitable habitat area for I. pacificus will expand in the interior regions of British Columbia and Washington State. However, the risk remains small given relatively low infection rates among I. pacificus. Further studies are required to better understand how this might change in the future.

Background: Spotted fever group rickettsioses, caused by rickettsiae of the spotted fever group, pose a significant zoonotic threat to public health. In endemic areas of Anhui Province, China, the ecology and transmission dynamics of these pathogens remain under investigation. Methods: We isolated a rickettsial strain from Haemaphysalis longicornis ticks collected from a wild hedgehog in the Dabie Mountain area. Molecular identification and phylogenetic analysis were employed to confirm the strain. Pathological examinations of the hedgehog's tissues were conducted to assess the potential impact of the infection. Results: The isolated strain was identified as R. heilongjiangensis strain AH-19. Pathological examination revealed significant tissue alterations, including cellular vacuolization, necrosis, and disarray of tissue architecture. It remains uncertain whether these changes were directly attributable to the rickettsial infection or other factors. Conclusions: The identification of R. heilongjiangensis strain AH-19 in H. longicornis suggests that hedgehogs may serve as reservoir hosts in the Dabie Mountain area.Further research is needed to clarify their role in the ecology and epidemiology of this pathogen, which could inform future public health strategies.

Background: Usutu virus (USUV) is an emerging flavivirus, closely related to West Nile virus (WNV), that has spread into Europe from Africa. Since Culex tarsalis Coquillett is an important vector for WNV transmission in the United States, we tested the ability of USUV to replicate in and be transmitted by these mosquitoes. Materials and Methods: USUV was used to infect 3-4 day-old Cx. tarsalis with 5.6 to 7.5 log₁₀ pfu/ml in goose bloodmeals. Saliva, heads, and bodies were collected on day 13 or 14 and analyzed by RT-qPCR for detection for USUV vRNA. Blotting paper punches were also collected daily to assess viral transmissibility. Results: The low and high dose blood meal resulted in 0% and 19.6% of the mosquitoes having established infections, respectively. All of the high dose had a dissemination of USUV RNA to the heads and none of the filter papers had detectable USUV RNA, but five of the capillary saliva collections were positive, representing 45.5% of the infected mosquitoes. Conclusions: Limited infection of Cx. tarsalis was observed when exposed to bloodmeals with greater than 107 pfu/mL of USUV, indicating this vector is not likely to have a key role in transmission of the virus.

Background and Objectives: Malaria airs a life-threatening risk in Tropical African countries, stemming from infection by Plasmodium species. This region is richly endowed by nature with a wealth of diverse and largely unexplored plants that hold the potential for managing this protozoan parasite. The currently accessible over-the-counter drugs for disease management often present affordability challenges for the average person, exacerbated by the parasite's increasing resistance to them. This study investigated the phytoconstituents present in the ethyl acetate fraction of Spilanthes filicaulis (EFSF) and explored the antimalarial effects of EFSF on mice infected with Plasmodium berghei. Methods: Standard methods and gas chromatography-mass spectrometry (GC-MS) were used to identify phytoconstituents. Chloroquine phosphate-sensitive P. berghei (NK-65) was intraperitoneally inoculated into Swiss mice. The in vivo antimalarial activity of EFSF was assessed at dose levels of 250, 500, and 750 mg/kg, using 4-day suppressive and curative antimalarial models. Parameters evaluated in the inoculated mice included rectal temperature (RT), body weight (BW), packed cell volume (PCV), level of parasitemia, and mean survival time (MST). Results: Steroids, alkaloids, flavonoids, tannins, saponins, terpenoids, and cardiac glycosides were the identified phytochemicals present in EFSF, and GC-MS alongside reveals the presence of 20 bioactive compounds predominantly fatty acids and alcohol esters. Significant prevention of reductions in RT, BW, and PCV was observed in the EFSF-treated groups dose dependently relative to the untreated group. In addition, EFSF-treated groups significantly (p < 0.05) suppressed parasitemia and exhibited chemosuppression of 79.46% and 77.38% in 4-day suppressive, whereas suppression of 59.74% and 58.66% in curative treatment, respectively, at 500 and 750 mg/kg thus consequently extending the MST of infected treated mice compared with the untreated group. Interpretation and Conclusion: Put together, the EFSF exhibited enhanced antimalarial efficacy against mice infected with P. berghei thus affirming that plants still maintain lead way as a potential source of novel antimalarial remedies.

Background: Acute encephalitis syndrome (AES) is a significant public health issue in India, attributed to various etiologies. In eastern Uttar Pradesh, Japanese encephalitis (JE) was the leading cause of AES (10-14% of total AES) until scrub typhus (ST), caused by Orientia tsutsugamushi, was identified in cerebrospinal fluid and blood samples of AES patients contributing more than 60% of AES cases. This study investigates the prevalence of JE-ST coinfection and compares clinical outcomes among JE mono-infection, ST mono-infection, and JE-ST coinfection. Materials and Methods: AES cases admitted to BRD Medical College, Gorakhpur, Uttar Pradesh, India, from January 1, 2017, to December 31, 2017, were included. JE and ST diagnosis was confirmed by serological (IgM) and molecular (PCR) tests. Statistical analysis was done to correlate clinical outcomes and infection group. Results: Total 1180 cases were tested positive for JE and/or ST. The prevalence of JE-ST coinfection was 8.9% among AES cases. JE mono-infection showed a mortality rate of 34.5%, ST mono-infection 13.4%, and JE-ST coinfection 9.5%. JE-ST co-infected cases experienced less severe clinical outcomes compared to mono-infected cases. Conclusion: JE-ST coinfection in AES cases is relatively common, with better clinical outcomes and lower mortality rates compared to JE or ST mono-infections.

Background: Clinical and epidemiological aspects of dengue have extensively been studied in India. However, limited data are available on social and behavioral aspects of dengue outbreak. We aimed to fill this gap and wish to study socioeconomic, demographic, and behavioral factors associated with dengue outbreak in the Gorakhpur region of eastern Uttar Pradesh, India. Methods: This retrospective observational study was conducted among dengue patients discharged from hospital. Data on sociodemographic, economic, and behavioral factors of dengue were collected telephonically using a structured questionnaire. Continuous and categorical variables were reported as mean ± SD and numbers (%), respectively. Logistic regression analysis was done to establish association between patient's characteristics, awareness, and preventive behavior. Results: Age group 19-45 years 156/232, males 159/232, urban residents 142/232, residing in pucca house 187/232, and from lower-income families 149/232 were mostly affected in this outbreak. Patients spent a median of Indian national rupees 20,000 on treatment. Only 10.8% of patients had Ayushman health insurance cards. Awareness about dengue infection was found in∼43% patients. Literates, middle income group, and professionals/semiprofessionals were significantly more aware about dengue disease, mosquito bite, and treatment than their counterparts. Travel history was significantly associated with dengue infection in the males of 19-45 years age group belonging to rural areas. Use of mosquito repellent, nets, wearing full sleeve clothes were significantly less in rural residents while barefoot walking was more frequently observed in this population. Use of mosquito repellent was significantly associated with income, and these were observed more in the middle-income group. Conclusion: People with low education level, residing in urban areas, residing in pucca houses, who travel frequently, and who belong to lower-income groups were majorly affected by this dengue outbreak. Less dengue awareness and not following preventive practices were found in them. Targeted health education campaigns in urban setting could prevent dengue and economic burden on these vulnerable groups.

Background: Between January 1, 2011, and December 31, 2017, over 12,000 case reports of Lyme disease (LD) were submitted to the California Reportable Disease Information Exchange for further investigation. The number of case reports has tripled compared to previous years, emphasizing the need for efficient estimation and classification methods. We evaluated whether estimation procedures can be implemented in a low-incidence state such as California to correctly classify a case of LD, similar to those procedures used in high-incidence states. Objective: The purpose of this study was to identify whether a minimum number of variables was sufficient to reliably classify cases in California and potentially reduce workload while maintaining the ability to track LD trends in California. Methods: To determine the relative value of diagnostic information, we compared five candidate logistic regression models that were used to classify cases based on information that varied in its degree of difficulty for collection. Results: Our results using California's surveillance data showed that automatically reported data were not sufficient, additional information such as, a patient's clinical presentation and travel history were necessary in a low-incidence state to improve the overall sensitivity of the models. Conclusion: This study may help inform public health surveillance efforts by demonstrating that both clinical and travel information are required to accurately classify a case of LD in a low-incidence state.