Scrub typhus (ST) is an acute febrile illness caused by Orientia tsutsugamushi (Hayashi, 1920) that is transmitted to humans through the bite of infected chiggers. In recent years, ST has re-emerged as a public health concern in Malaysia. In 2024, more than 50 laboratory-confirmed human cases of ST were reported in Pahang. A collaborative investigation was undertaken on a subset of 26 cases to identify potential vector sources and animal hosts associated with O. tsutsugamushi transmission. Chigger-based sampling was conducted by trapping small mammals in suspected infection hotspots, including residential surroundings, frequently visited locations, and work areas of confirmed cases. A total of 95 small mammals were captured, of which 65.3% infested with chiggers (Chigger index, CI = 40.3). Overall, 3,831 on-host chiggers were collected and identified morphologically, with Leptotrombidium deliense (Walch, 1922) being the most frequently collected species (46.7%), followed by Ascoschoengastia indica (Hirst, 1915) (33.9%), Leptotrombidium spp. (18.4%), and Helenicula mutabilis (Gater, 1932) (1.0%). DNA was extracted from 188 pooled chigger samples (N = 3,450) as well as from blood and spleen tissues of captured animals, and screened for O. tsutsugamushi using nested PCR targeting the 56-kDa TSA gene. Notably, O. tsutsugamushi was detected in 13 (6.9%) chigger pools solely of L. deliense, and in 11 spleens and six blood samples. Phylogenetic analysis showed high nucleotide similarity (97-100%), with the Karp genotype predominating, followed by Gilliam, Kato, and TA763 genotypes. These findings confirm the presence of O. tsutsugamushi in vectors and animal hosts in Pahang, highlighting the region as a potential ST hotspot, and underscoring the need for continued monitoring and control efforts.

Chiggers (Acariformes: Trombiculidae) are ectoparasites of small mammals and important vectors of scrub typhus, yet their taxonomy and molecular diversity in Southeast Asia remain poorly resolved. This study represents the first DNA barcoding and phylogenetic assessment of chiggers from small mammals across Peninsular Malaysia, integrating mitochondrial (COI) and nuclear (28 S rDNA) genes. A total of 192 chiggers representing 11 morphospecies from six genera were sequenced, with tree topologies inferred using maximum likelihood and supported by multiple species delimitation methods. The COI gene discriminated five species as monophyletic, while analysis of the 28 S rDNA gene clarified phylogenetic relationships within Walchia and Leptotrombidium. Discordance between morphological and molecular boundaries in several taxa, particularly Gahrliepia fletcheri, Leptotrombidium deliense, and Walchiella oudemansi, suggests the existence of cryptic lineages and potential regional diversification. Importantly, this study provides the first molecular records for eight species, including the only barcodes from the genera Gahrliepia and Walchiella worldwide. These findings provide important resources for the molecular identification of Southeast Asian chiggers and underscore the need for integrative approaches combining morphology, molecular data, and biogeography to resolve complex species boundaries and improve vector surveillance for mite-borne diseases.

ObjectiveRodents and other sympatric small mammals serve as reservoir hosts for zoonotic diseases including scrub typhus and hemorrhagic fever with renal syndrome (HFRS), with their ectoparasitic mites (chiggers and gamasid mites) acting as vectors. This 12-month study investigated mite infestation, community structure, seasonal dynamics, and climatic drivers on small mammal hosts in Jingha, southern Yunnan, China–a known scrub typhus and HFRS.MethodsWe calculated infestation metrics (prevalence [PM], mean abundance [MA], mean intensity [MI], constituent ratio [Cr]) and community indices (richness [R], Shannon-Wiener diversity [H], Pielou evenness [E], Simpson dominance [D]). Generalized additive models (GAMs) analyzed spatiotemporal and climatic patterns.ResultsFrom 2,424 small mammal hosts (15 species), we collected 142,471 mites (158 species). Chiggers (109 species, 109,093 individuals) significantly outnumbered gamasid mites (49 species, 33,378 individuals; P < 0.001) and showed greater richness (R = 9.31 vs. 4.61), diversity (H = 2.13 vs. 1.97). Rattus andamanensis was the dominant host. Chigger infestation (PM = 86.14%, MA = 45.01, MI = 52.25) significantly exceeded gamasid mites (PM = 67.16%, MA = 13.77, MI = 20.50; P < 0.001), particularly on female and adult hosts. Four species dominated (Cr = 65.40%): chiggers Walchia micropelta, Ascoschoengastia indica, Leptotrombidium deliense, and gamasid mite Laelaps nuttalli. Primary vectors among 23 species included chiggers L. deliense, A. indica, L. scutellare, and gamasid Laelaps echidninus (Cr = 38.46%).ConclusionCommunity indices fluctuated monthly without distinct peaks, while dominant species abundances varied significantly. Climatic factors exerted species-specific effects: L. deliense peaked in July (30.0 mites/host; 95% CI: 29.2–30.8) coinciding with maximal temperatures, while A. indica peaked in August (25.1 mites/host; 95% CI: 24.5–25.8), lagging peak rainfall. Non-overlapping confidence intervals indicated temporal niche separation between species. Mite-mite networks revealed positive intragroup correlations but no significant intergroup correlations. Host-mite networks demonstrated low host specificity: individual hosts harbored multiple mite species, and individual mite species parasitized multiple hosts. High mite abundance, co-occurrence of multiple vector species, and low host specificity collectively elevate transmission risks and persistence of scrub typhus and HFRS.

ObjectiveThe present study aims to investigate the seasonal dynamics of main vectors of scrub typhus, and thereby provide scientific information for the surveillance and control of the disease.MethodsA field investigation lasting for 12 consecutive months was conducted at a fixed survey site (Waxi Village) in Binchuan County (a focus of scrub typhus), Yunnan Province of southwest China between 2019 and 2020. Based on the taxonomic identification of all collected chigger mites, the three vector chigger species of scrub typhus (Leptotrombidium deliense, L. scutellare and L. imphalum) were screened out as the object of this study. The constituent ratio (Cr), prevalence (PM), mean abundance (MA), and mean intensity (MI) were calculated to reflect the mite infestation status. The Levins’ niche breadth (Bi) and Pianka’s proportional similarity ratio (Oij) were used to calculate the ecological niche breadth and niche overlap of chiggers on different host species and temporal series.ResultsThese three vector chigger species were the dominant mites at the survey site, accounting for 60.72% of the total 115 chigger species (Cr=60.72%, 132,160/217,671). In seasonal fluctuations, L. deliense showed two peaks in summer and autumn, and the highest peak was in August of summer with highest infestation indexes (Cr=44.29%, MA=322.48, MI=422.56) on the hosts. Leptotrombidium imphalum mainly appeared in summer and autumn, and peaked in September (Cr, MA and MI) and October (PM) of early autumn. Leptotrombidium scutellare mainly appeared in November, December and January, and peaked in November of late autumn (Cr=66.09%) and December of early winter (Cr=33.83%). Leptotrombidium deliense had the widest temporal niche (Bi=0.248) and L. scutellare had the widest host niche (Bi=0.268). Leptotrombidium deliense and L. imphalum had the highest temporal niche overlap (Oij=0.715) and host niche overlap (Oij=0.986). The monthly average temperature significantly affected the seasonal fluctuation of L. scutellare.ConclusionThe three vector chigger species can parasitize a wide range of hosts with low host specificity, and their coexistence as the dominant mites at the survey site increases the potential risk of transmission and focus persistence of relevant mite-borne zoonoses. Leptotrombidium deliense and L. imphalum have similar seasonal distribution patterns (summer-autumn type) and host selection, and L. scutellare has a different type of seasonal fluctuation, autumn-winter type. The temporal and host niches of L. scutellare are very different from those of L. deliense and L. imphalum. The temperature is the most important climate factor that drives the seasonal dynamics of vector chiggers.

Trombiculid mites (Acariformes) are unique among arthropods of medical importance in that only the larval instar (chigger) is parasitic, which can result in the transmission of zoonotic scrub typhus. The use of molecular approaches for chigger species discrimination has been very limited until recently, especially for those parasitizing bird hosts, where data remain scarce. Here, we aimed to generate DNA barcodes of chiggers parasitizing birds in Malaysia based on the mitochondrial cytochrome c oxidase subunit I (COI) gene following DNA extraction, PCR and sequencing. Fifty-four COI sequences from 8 bird-associated chigger species in Malaysia were combined with 50 GenBank sequences comprising 7 genera from various countries for DNA barcode and phylogenetic analysis. The correct identification rates for the 95 COI barcodes were 96.84% (Best Match) and 86.31% (Best-Close Match). DNA barcode analyses effectively clustered the 8 nominal species from this study into their respective genera. Genetic divergence of less than 3% was observed within Ascoschoengastia lorius, Neoschoengastia gallinarum, Parascoschoengastia heynemani, Leptotrombidium imphalum, and Blankaartia acuscutellaris, all of which formed a monophyletic clade, confirming their conspecific nature. Conversely, intraspecific divergences of 17.64%, 15.49%, and 11.63% were obtained for Toritrombicula densipiliata, Odontacarus audyi, and Leptotrombidium deliense. These divergences, supported by evidence of distinct entities through delimitation analyses, indicate potential cryptic diversity within these populations. In conclusion, this study represents the first molecular genetic analysis of bird chiggers in Malaysia, revealing varying levels of genetic divergence. Our findings highlight the utility of DNA barcoding for understanding chigger diversity and aiding in accurate identification.

Background & objectivesOrientia tsutsugamushi, a bacterial pathogen of scrub typhus, is transmitted to humans through the bite of infected chigger mites, and rodents are the natural hosts of the disease vector. The traditional practices of the tribal ethnic groups (Mizo) of Mizoram state such as capturing and consumption of rat meat collected from the agricultural fields could be one source of vector-disease transmission route. The present study aimed to detect and identify the pathogen of scrub typhus from vectors collected from rice field rats which were captured by farmers for meat consumption purposes.MethodsOne hundred and fifty-six freshly captured rice field rats were examined for ectoparasites. Detection and genotyping of O. tsutsugamushi from ectoparasites were done by real-time PCR and conventional PCR using species-specific primers. Rodents and ectoparasites were identified down to the species level using morphological and molecular techniques.ResultsRice field rats were identified as Rattus tanezumi and Rattus nitidus. A total of 7973 trombiculid mites collected from 156 rats were identified as Leptotrombidium deliense, Leptotrombidium fletcheri, and Leptotrombidium chiangraiensis. Of these, 26 pools of L. deliense and 15 pools of L. fletcheri tested positive for O. tsutsugamushi, and the O. tsutsugamushi detected belongs to Kato and Karp-related genotypes.Interpretation & conclusionThe present study reported the presence of O. tsutsugamushi-infected chigger mites in the captured rats (R. tanezumi and R. nitidus). Direct contact with the rats as a result of rat-eating habits may correspond to the high incidence rate of scrub typhus cases in Mizoram. Preventive measures are crucial for the control of scrub typhus disease in Mizoram.

Background. Scrub typhus is a mite-borne disease caused by Orientia tsutsugamushi (Ot), primarily transmitted by the chigger mites Leptotrombidium deliense (L. deliense) and Leptotrombidium scutellare (L. scutellare). To effectively control the transmission of this disease, it is essential to clarify the spatial distribution of suitable habitats for its vector species. This research focuses on estimating the global potential distribution of Leptotrombidium deliense and Leptotrombidium scutellare under both current and projected future climate conditions. Additionally, the study aims to evaluate the influence of key climatic variables on the geographical patterns of these two vectors. Methods. Data on species distribution were obtained from the Global Biodiversity Information Facility (GBIF) and from publicly published literature in databases such as Web of Science and PubMed. The environmental variables were downloaded from WorldClim Global Climate Database. The Maximum Entropy Model was used to evaluate the contribution of elevation, slope, aspect and nineteen bioclimatic variables to vector survival, as well as to predict the suitable area for the vectors. Results. It indicated that L. deliense predominantly occurs in southern China, India, Australia, and Southeast Asian regions. In contrast, L. scutellare is largely restricted to southern and eastern coastal areas of China. L. deliense displays greater adaptability to tropical zones, whereas L. scutellare shows higher survival potential in temperate zones. Specifically, L. deliense demonstrates significant sensitivity to precipitation during both the warmest and wettest quarters, indicating a ecological preference for hot and humid tropical environments, while L. scutellare is more sensitive to precipitation of warmest quarter. Under the SSP5-8.5 scenario, the suitable habitat areas for the two species are expected to increase by 84.58% and 148.50%, respectively, compared to historical levels. Climate change will have a significant impact on the expansion of suitable habitats for these species. Conclusions. To effectively prevent disease outbreaks and their spread, it is recommended to further strengthen disease surveillance and control measures in highly suitable areas where vector organisms are already present. Simultaneously, entry-exit quarantine and vector invasion monitoring capabilities should be enhanced in other highly suitable regions to prevent the introduction and establishment of foreign vector species.

Chiggers (chigger mites) are a group of tiny arthropods, and they are the exclusive vector of Orientia tsutsugamushi (Ot), the causative agent of scrub typhus (tsutsugamushi disease). Dehong Prefecture in Yunnan Province of southwest China is located on the China-Myanmar border and is an important focus of scrub typhus. Based on the field surveys in Dehong between 2008 and 2022, the present paper reports the infestation and ecological distribution of chiggers on the body surface of rodents and other sympatric small mammals (shrews, tree shrews, etc.) in the region for the first time. The constituent ratio (Cr), prevalence (PM), mean abundance (MA), and mean intensity (MI) were routinely calculated to reflect the infestation of small-mammal hosts with chiggers. Additionally, the species richness (S), Shannon-Wiener diversity index (H), Simpson dominance index (D), and Pielou's evenness index (E) were calculated to illustrate the chigger community structure. Preston's log-normal model was used to fit the theoretical curve of species abundance distribution, and the Chao 1 formula was used to roughly estimate the expected total species. The "corrplot" package in R software (Version 4.3.1) was used to analyze interspecific relationships, and the online drawing software was used to create a chord diagram to visualize the host-chigger associations. From 1760 small-mammal hosts, a total of 9309 chiggers were identified as belonging to 1 family, 16 genera, and 117 species, with high species diversity. The dominant chigger species were Leptotrombidium deliense, Walchia ewingi, and Gahrliepia longipedalis, with a total Cr = 47.65% (4436/9309), among which L. deliense is the most important vector of Ot in China. The overall infestation indexes (PM, MA, and MI) and community parameters (S, H, and E) of chiggers in the mountainous areas and outdoors were higher than those in the flatland areas and indoors, with an obvious environmental heterogeneity. Leptotrombidium deliense was the dominant species in the flatland and indoors, while G. longipedalis was the prevalent species in the mountainous and outdoor areas. The species abundance distribution of the chigger community conformed to log-normal distribution with the theoretical curve equation: S(R)'=28e-[0.23(R-0)]2, indicating the existence of many rare species and only a few dominant species in the community. The expected total number of chigger species was roughly estimated to be 147 species, 30 more than the 117 species actually collected, suggesting that some uncommon species may have been missed in the sampling survey. The host-parasite association analysis revealed that one host species can harbor different chigger species, and one chigger species can parasitize different host species with low host specificity. A positive or negative correlation existed among different chigger species, indicating a cooperative or competitive interspecific relationship. The species diversity of chiggers is high in Dehong on the China-Myanmar border, and a large host sample is recommended to find more uncommon species. There is an obvious environmental heterogeneity of the chigger community, with different species diversity and dominant species in different environments. The low host specificity of chiggers and the occurrence of a large number of L. deliense in Dehong, especially in flatland areas and indoors, would increase the risk of persistent transmission of scrub typhus in the region.

Objectives: “Q fever,” which is caused by Coxiella burnetii, is endemic in India. In addition to livestock, rodents have also been reported to be associated with enzootic maintenance, favoring pathogen transmission. Currently, however, no data are available on the role of rodents in “Q fever” transmission in India. Methods: A cross-sectional study was undertaken in 39 Puducherry villages to screen Coxiella burnetii in synanthropic rodents (rats and shrews) and their ectoparasites (ticks, mites, and fleas) by real-time and conventional PCR protocols targeting the pathogen specific IS 1111 and com 1 genes. Results: One hundred forty animals were trapped (107 shrews and 33 rats). The ticks, mites, and fleas infesting the rodents were identified as Rhipicephalus sanguineus, Leptotrombidium deliense and Schoengastiella spp., and Xenopsylla cheopis, respectively. PCR screening of the DNA extracted from the rodent/shrew blood samples and their ectoparasites tested negative for C. burnetii. Conclusions: Synanthropic rodents, such as rodents/shrews and their ectoparasites do not have a pivotal part in the enzootic maintenance and spread of Q fever to humans and livestock in Puducherry.

Background: Scrub typhus is prevalent in many districts of South Bengal throughout the year where an average temperature of 20–35°C, which contributes to the spread of Leptotrombidium deliense. However, its diagnosis remains complicated by the lack of readily available and validated assays, the non-specificity of clinical symptoms on admission, and even non-availability of the pathognomonic eschar in most of the cases. Aims and Objectives: This study was carried out to evaluate the rapid immunochromatographic test (RICT) for early detection of scrub typhus for using it as an early diagnostic tool at the field level. Materials and Methods: This cross-sectional study in which 181 serum samples from clinically suspected cases (after excluding dengue, malaria, Japanese encephalitis, and typhoid fever) collected over 13 months were processed for the detection of immunoglobulin M (IgM) antibodies for scrub typhus by enzyme-linked immunosorbent assay (ELISA) and rapid test. Results: Considering IgM ELISA for scrub typhus as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value for RICT were found to be 100%, 86.87%, 50%, and 100%, respectively. Conclusion: RICT is a simple, rapid, and reliable assay for diagnosis of scrub typhus, capable of providing accurate results quickly and is highly suitable for field deployment in remote areas with limited medical support.

Scrub typhus is one of the most neglected tropical diseases, a leading cause of acute undifferentiated febrile illness in areas of the 'tsutsugamushi triangle', diagnosed frequently in South Asian countries. The bacteria Orientia tsutsugamushi is the causative agent of the disease, which enters the human body through the bite of trombiculid mites (also known as chiggers) of the genus Leptotrombidium deliense. Diagnosis of the disease is challenging, as its early symptoms mimic other febrile illnesses like dengue, influenza and corona viruses. Lack of rapid, reliable and cost-effective diagnostic methods further complicates the identification process. Northeast India, a mountainous region with a predominantly rural tribal population, has witnessed a resurgence of scrub typhus cases in recent years. Various ecological factors, including rodent populations, habitat characteristics and climatic conditions, influence its prevalence. Entomological investigations have confirmed the abundance of vector mites, highlighting the importance of understanding their distribution and the probability of transmission of scrub typhus in the region. Proper diagnosis, awareness campaigns and behavioural interventions are essential for controlling scrub typhus outbreaks and reducing its impact on public health in Northeast India. Further research and community-based studies are necessary to accurately assess the disease burden and implement effective prevention strategies.

Chigger mites are the vector of scrub typhus. This study estimates the infestation status and ecological characteristics of chiggers on the chestnut white-bellied rat Niviventer fulvescens in Southwest China between 2001 and 2019. Chiggers were identified under the microscope, and infestation indices were calculated. The Preston's log-normal model was used to fit the curve of species abundance distribution. A total of 6,557 chiggers were collected in 136 of 342 N. fulvescens rats, showing high overall infestation indices (prevalence=39.8%, mean abundance=19.2, mean intensity=48.2) and high species diversity (S=100, H'=3.0). Leptotrombidium cangjiangense, Neotrombicula japonica, and Ascoschoengastia sifanga were the three dominant chigger species (constituent ratio=42.9%; 2,736/6,384) and exhibited an aggregated distribution among different rat individuals. We identified 100 chigger species, with 3 of them (Leptotrombidium scutellare, Leptotrombidium wenense, and Leptotrombidium deliense) as the main vectors of scrub typhus in China and nine species as potential vectors of this disease. Disease vector occurrence on N. fulvescens may increase the risk of spreading scrub typhus from rats to humans. Chigger infestation on N. fulvescens varied significantly in different environments. The species abundance distribution showed a log-normal distribution pattern. The estimated number of chigger species on N. fulvescens was 126 species.

Chigger mites are the exclusive vector of scrub typhus. Based on field investigations of 91 survey sites in 5 provincial regions of Southwest China, this paper reported variations of chigger infestation on the oriental house rat (Rattus tanezumi) along various environmental gradients. A total of 149 chigger species were identified from 2919 R. tanezumi in the 5 provincial regions, and Leptotrombidium deliense (a major vector of scrub typhus in China) was the first dominant chigger species, followed by Ascoschoengastia indica and Walchia ewingi. Rattus tanezumi had a stable overall prevalence (PM = 21.10%), mean abundance (MA = 7.01), and mean intensity (MI = 33.20) of chiggers with the same dominant mites in the whole Southwest China in comparison with a previous report in Yunnan Province, but chigger infestations on R. tanezumi varied along different environmental gradients. Rattus tanezumi in mountainous landscape had a higher infestation load of chiggers with higher species diversity than in flatland landscape. The infestation was higher at lower altitudes and latitudes. A high intensity of vegetation coverage was associated with high infestations. The results reflect the environmental heterogeneity of chiggers on the same host species. Warm climate and high relative humidity are beneficial to chigger infestation on R. tanezumi.

Mites act as the vectors of zoonotic vector-borne disease scrub typhus caused by the rickettsial pathogen Orientia tsutsugamushi. In India, scrub typhus is transmitted by the mite Leptotrombidium deliense. Rodents are the reservoirs and support the spread of this disease. Sarcoptes scabiei or the itch mite is causing scabies which is a common skin infection in India. Dermatitis, trombiculosis, and mite dust allergy are common mite-borne diseases transmitted by Pyemotidae family. D. brevis folliculorum and Demodex brevis are two major mite species found on humans also causing a disease; "Demodicosis", common in India. Dermanyssus gallinae, fowl mite causes pruritis in poultry birds, transmits infections to poultry workers when they come into contact with birds. There is a re-emergence of mite-borne diseases, especially scrub typhus, in many parts of India requiring urgent attention for its control. This review is aimed to update the available information on mites and mite transmitted diseases prevalent in India to highlight the importance of rodent and chigger mite vector control to prevent forthcoming mite-borne diseases in India.

SFTSV, a tick-borne bunyavirus causing a severe hemorrhagic fever termed as severe fever with thrombocytopenia syndrome (SFTS). To evaluate the potential role of rodents and its ectoparasitic chiggers in the transmission of SFTSV, we collected wild rodents and chiggers on their bodies from a rural area in Qingdao City, Shandong Province, China in September 2020. PCR amplification of the M and L segments of SFTSV showed that 32.3% (10/31) of rodents and 0.2% (1/564) of chiggers (Leptotrombidium deliense) from the rodents were positive to SFTSV. Our results suggested that rodents and chiggers may play an important role in the transmission of SFTSV, although the efficiency of chiggers to transmit SFTSV needs to be further investigated experimentally.

Scrub typhus (tsutsugamushi disease) is caused by the causative agent, Orientia tsutsugamushi, and it is a widespread zoonosis and vector-borne disease. Chigger mites (trombiculid mites) are the exclusive vectors of this disease. To date, more than 500 species of chigger mites have been documented in China, and six of them have been proved to be the main effective vector species of scrub typhus: Leptotrombidium deliense, L. scutellare, L. rubellum, L. sialkotense, L. wenense and L. insulare. The present paper reviewed the research history and progress of the six vector chigger species in China, which covered their history of nomenclature, vector roles, morphological identification, life cycle, distribution, host selection and seasonal fluctuation, etc.

Orientia tsutsugamushi is a mite-borne bacterium belonging to the family Rickettsiaceae and is responsible for a disease called scrub typhus in humans, which is transmitted by the vector mite Leptotrombidium deliense (common ectoparasite on rodents) in most of Asian countries including India. The study conducted in selected villages of Karnal and Kaithal districts of Haryana state, India revealed four species of rodents - Rattus rattus, norveigicus, Bandicota indica and Suncus murinus. Dust mite Dermatophagoides farina; chigger mite L. deliense and fleas Xenopsylla astia and X. cheopis were prevalent on the rodents.

The current and future risk of spread of Leptotrombidium deliense and Leptotrombidium scutellare in mainland China

Scrub typhus is a vector-borne, zoonotic disease caused by Orientia tsutsugamushi. Several members of the genus Leptotrombidium have gained importance due to their potential role as vectors as well as reservoirs for O. tsutsugamushi. The larvae of Leptotrombidium species are primary parasites of ground-dwelling rodents. However, changes in climate, host specificity makes them to adapt to other animals and play a role in the perpetuation of various (re)emerging pathogens between animals and humans. Two male mongrel dogs aged six months were presented to the College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Mizoram, India with a history of skin lesions and intense pruritus. Routine skin scraping examination of samples revealed the presence of Leptotrombidium deliense larvae. Considering the public health importance of L. deliense infestation, an attempt was made to screen the dogs for O. tsutsugamushi and other haemoprotozoans. Microscopic and molecular tests were negative for haemoprotozoan parasites and O. tsutsugamushi, respectively. Both the dogs were successfully treated with parenteral ivermectin and topical fipronil spray.

The emergence of drug-resistant lice, acari, and their associated pathogens (APs) is associated with economic losses; thus, it is essential to find new appropriate therapeutic approaches. In the present study, a subtractive proteomics approach was used to predict suitable therapeutics against these vectors and their infectious agents. We found 9701 proteins in the lice (Pediculus humanus var. corporis) and acari (Ixodes scapularis, Leptotrombidium deliense), and 4822 proteins in the proteomes of their APs (Babesia microti, Borreliella mayonii, Borrelia miyamotoi, Borrelia recurrentis, Rickettsia prowazekii, Orientia tsutsugamushi str. Boryong) that were non-homologous to host proteins. Among these non-homologous proteins, 365 proteins of lice and acari, and 630 proteins of APs, were predicted as essential proteins. Twelve unique essential proteins were predicted to be involved in four unique metabolic pathways of lice and acari, and 103 unique proteins were found to be involved in 75 unique metabolic pathways of APs. The sub cellular localization analysis of 115 unique essential proteins of lice and acari and their APs revealed that 61 proteins were cytoplasmic, 42 as membrane-bound proteins and 12 proteins with multiple localization. The druggability analysis of the identified 73 cytoplasmic and multiple localization essential proteins revealed 22 druggable targets and 51 novel drug targets that participate in unique pathways of lice and acari and their APs. Further, the predicted 42 membrane bound proteins could be potential vaccine candidates. Screening of useful inhibitors against these novel targets may result in finding novel compounds efficient for the control of these parasites.