REVIEW ARTICLES Year : 2023  |  Volume : 60  |  Issue : 1  |  Page : 1-10

Current status of mites and mite-borne diseases in India

R Govindarajan1, V Rajamannar1, Ashwani Kumar2, Philip P Samuel1
1 Division of Vector-Borne and Zoonotic Diseases, ICMR-Vector Control Research Centre Field Station, Madurai, Tamil Nadu, India
2 ICMR-Vector Control Research Centre, Puducherry, India

Date of Submission19-Apr-2022Date of Acceptance30-Sep-2022Date of Web Publication5-Apr-2023

Correspondence Address:
Philip P Samuel
Scientist D, ICMR-Vector Control Research Centre Field Station, Department of Health Research, 4, Sarojini Street, Chinnachokkikulam, Madurai-625002, India.
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/0972-9062.361175

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.

Keywords: Mite; distribution; disease; pathogen; genus; species

How to cite this article:
Govindarajan R, Rajamannar V, Kumar A, Samuel PP. Current status of mites and mite-borne diseases in India. J Vector Borne Dis 2023;60:1-10
How to cite this URL:
Govindarajan R, Rajamannar V, Kumar A, Samuel PP. Current status of mites and mite-borne diseases in India. J Vector Borne Dis [serial online] 2023 [cited 2023 Apr 6];60:1-10. Available from: http://www.jvbd.org//text.asp?2023/60/1/1/361175   Introduction 

Mites are very tiny, hemimetabolous microscopic parasites. Adults and nymphs are showing with four pairs of legs, but larvae have three pairs[1]. Globally, more than 48,000 different mite species were recorded which are harmless to humans and found beneficial to the ecosystem[2]. On the other hand, approximately 250 mite species are found to have public health importance[3]. The life cycle of many mite species requires less than four weeks and can be as short as eight days[4]. Scrub typhus is transmitted by the mite Leptotrombidium deliense and the rodents are the reservoirs that support the spread of this disease. Sarcoptes scabiei or the itch mite causes scabies which is a common skin infection in India. Dermatitis, trombiculosis, and mite dust allergy are common mite-borne diseases transmitted by Pyemotidae family. Demodex folliculorum and Demodex brevis are two major mite species found in humans causing a disease; “Demodicosis”, common in India. Dermanyssus gallinae, fowl mite causes pruritis to poultry birds, transmits infections to poultry workers when they come into contact with the birds. Dust mites are extremely small, live in house dust, feeding on the dead skin cells that people regularly shed, known for causing allergies. Thus, many mite species are responsible for the spread of diseases like itching, pulmonary and intestinal acariasis, urinary, allergic diseases, and dermatitis in humans[5].

Three major mite infestations and infections were recorded, (1) human mites dermatoses (2) animal and plant, and plant-insect mite infestations and, (3) bacterial pathogens infections[8]. Scrub typhus was reported in India for a long time. Since this mite-borne scrub typhus infection is a resurfacing disease in India, this review updates the current knowledge in India which will be helpful to the researchers and public health officials to undertake effective control strategies[6].

  MATERIAL & METHODS 

Literature review

The online database PubMed of National Library of Medicine, USA was used for the retrieval of references and abstracts subjected to search terms “mites” and “mite-borne diseases” listed in life sciences and biomedical topics. MeSH terms and subheadings like mites-borne diseases, the biology of mites; and mites-borne infections were used for literature review. For the management of reference information, EndNote Version 9.0.1©1998-2005 of Thomson, Mendeley Reference Manager Version 2.44.0©2020 of Mendeley Ltd was used. Journals, books, book sections, conference proceedings, web pages, and local reports were the different types of documents used in the literature review

Spot map

Based on mite-borne diseases clinical data and outbreaks, spot maps were created by using EpiMap in EpiInfoTM 7.2.2.6 website of CDC, Atlanta, USA.

Mites and mite-borne diseases

Scrub typhus and Trombiculidae mites

A billion people present in the Asia-Pacific region are at risk and about a million people are affected with scrub typhus every year[7]. In South-East Asian region, the dominant vectors of scrub typhus are Leptotrombidium deliense and L. akamushi. In India, L. deliense is dominant and the only vector for the spread of scrub typhus[8].

Scrub typhus is distributed in an uneven, irregular pattern of distribution in an environment[9],[10]. Larval Trombiculid mites (or) chiggers are aggregated in the groups termed as “mite islands”[9], that provide a suitable habitat (vegetation structure such as abandoned plantations, gardens, or rice fields, overgrown forest clearings, shrub fields, and forests, riverbanks, and grassy fields) and climatic conditions (temperature, humidity, and rainfall) for their survival[6],[9],[10],[11]. Within the mite islands, there may be a limited area of intensive transmission of rickettsiae called “typhus island”[12]. Chiggers are usually found on parts of the animal hosts that have been in contact with the ground. They are also localized in and around the ears[13],[14]. Chiggers are generally considered habitat- and host-specific, and sometimes the larval stage of mites can occur on multiple host taxa[15]. The “tsutsugamushi triangle” is the endemic region of scrub typhus that comprises of major Asia-Pacific region that varies with 0 to 30% mortality depending on the geographical regime[8].

In India, 204 chigger species under 28 genera of the family Trombiculidae, have been described, significant in public health[16] “scrub typhus”, an acute febrile disease caused by the bacterial pathogen Orientia tsutsugamushi (formerly Rickettsia tsutsugamushi) (Family: Rickettsiaceae), transmitted by the biting of larval mites of Leptotrombidium species (chiggers) coming under the Trombiculidae family. Mites carry the bacterium from larval stages to adults and their progenies through transmedial and transovarial transmission[17].

Medically important scrub typhus (or) tsutsugamushi disease is the vector-borne rickettsial disease transmitted by Trombiculid mites (Acari: Trombiculidae), distributed worldwide (except in the continent of Antarctica), diverse in the subtropical, tropical, and southern temperate zones, and act as vectors for scrub typhus[7],[9],[11]. Trombiculidae is one of the largest families in the Acari group that includes more than 3000 species of mites[18]. Scrub typhus is caused by a gram-negative bacterium, Orientia tsutsugamushi, and is transmitted by the larval stage of mites (“chiggers”) in the family Trombiculidae. Scrub typhus was described first in Japan in 1899, caused by the pathogen α-proteobacteria, O. tsutsugamushi (earlier called Rickettsia orientalis or R. tsutsugamushi)[18]. In nature, more than 45 species of trombiculid mites are known to be infected with O. tsutsugamushi[20]. Humans are accidental hosts in the transmission of the disease.

The earlier outbreaks had been associated with the predominance of the vector L. deliense in India. But, in the recent outbreaks, L. deliense was missing as a vector, and the emergence of Schoengastiella ligula as the primary vector in the outbreak of Kurseong district, West Bengal, India[21]. Scrub typhus is most prevalent in the hilly forest belt which is full of thick vegetation, suitable habitat for the mite to survive in the grassy fields, shrubby areas, forests, and cleared forests[22]. The district of Darjeeling, West Bengal has also been historically considered as one of the scrub typhus endemic areas in the country with scrub typhus outbreaks reported until the 1960s[22]. Thereafter, for a long time, no outbreaks were reported which continued till 2005. The outbreaks of scrub typhus were again reported in 2005[22].

Recently, we undertook the surveillance for the scrub typhus chigger mite vector on the rodents in Vellore, Krishnagiri, Dharmapuri[23] and Madurai districts in Tamil Nadu state and Thiruvananthapuram district in Kerala[24]. Our studies conducted in Madurai recorded four species of trombiculid mites[25],[26],[27]. Similar studies conducted by us in Vellore district, Tamil Nadu showing 18 species of trombiculid mites[28]. Our survey conducted in the scrub typhus endemic Thiruvananthapuram district, Kerala reported 23 species of trombiculid mites. First record of 19 species of Trombiculidae species and 1 species of Laelaptidae were reported from our studies in Kerala[29]. Similarly, we recorded for the first time 14 species of Trombiculidae and 3 species of Laelaptidae from Tamil Nadu[29]. A rapid protocol for clearing, staining, and mounting of Arthropoda: Trombiculidae, Pediculidae, and Pulicidae was developed[30]. Detected Orientia tsutsugamushi in novel Trombiculid mite species in northern Tamil Nadu, India[31]. Three species of dust mites and 5 species of storage mites were recorded in different Indian cities/states[32]. In Kolkata, West Bengal, a study conducted during 2017 showed a total of 51 species belonging to 34 genera and 17 families[33].

Scrub typhus outbreaks in India

Scrub typhus was recognized in India as rickettsial typhus fever during 1917[34]. In 1932, the first cases of scrub typhus were reported in India[35] and the case was believed to be a tick-borne disease, due to the lack of serological tests. Similarly, in 1934, scrub typhus was reported among personnel from Shimla hills, India[36]. An investigation has reported the presence of Trombicula deliensis (L. deliense) on rodents and shrews in the Shimla hills for the transmission of scrub typhus[37]. During 1935, the presence of typhus was serologically confirmed by Weil–Felix OXK[38], but no positive cases were showing with eschars in India[39] reported from two outbreaks of scrub typhus occurred during 1937–1938 and 1939–1942, was confirmed by Weil–Felix serology tests[40]. A major outbreak of scrub typhus occurred at the Assam-India-Myanmar border and West Bengal among the military personnel during World War II[41], and another major outbreak also occurred during 1965 during the Indo-Pak war[22],[42]. The disease also resurged at the Pakistan border of India in 1990[22].

In the pre-antibiotic era, mortality rates were as high as 40–45% due to scrub typhus[43]. Changes in human lifestyle patterns, modern drug developments, and the widespread use of insecticides to control the vectors and also decrease the spread of disease incidence in India[22],[44]. Epidemiology and entomological studies also confirm the occurrence of scrub typhus all over India.

Scabies and Sarcoptidae mites infection

Scabies is an infestation caused by the mite Sarcoptes scabiei. Sarcoptes scabiei (or) the itch mite is a parasitic mite of the Sarcoptidae family of mites that burrows into the skin and causes the disease scabies. This mite is distributed throughout the world. Humans are not the only mammals that can become infected. Sarcoptes scabiei is a microscopic mite that burrows in the epidermis and infests the skin of its host[45] with over 100 described species[46].

Every year more than 300 million cases of scabies are recorded in the world[47]. It is endemic in some Indian villages and reported more in developing countries[48], where the prevalence is up to 100%[49]. In most of the developed countries, scabies is reported in hospitals, nursing homes, and long-term care facilities in epidemic proportion. The highest rates of infections are found in countries with hot, tropical climates, where the infestation is endemic.

In India, scabies is more prevalent in overcrowded communities with low socioeconomic conditions. 81% of inmates of an orphanage in the rural area of Maharashtra, India, were found to suffer from scabies and all inmates were successfully treated with mass scabies treatment and health education. In the rural community the prevalence rate of scabies is 13%[50], and topical permethrin and oral ivermectin drugs are used to control human scabies. The mite Sarcoptes scabiei var hominis is an obligate human parasitic mite of about 300–400 microns in size, causes sarcoptic mange (scabies) in humans and other mammals[51]. Humans were the original host of Sarcoptes, and all other hosts were secondarily infested[52]. Scabies transmission is by direct skin-to-skin contact. Crusted scabies is a rare type of scabies characterized by uncontrolled proliferation of mites in the human skin caused primarily by female scabies mite, Sarcoptes scabiei var hominis, common in HIV-infected patients[48]. Scabies is an important and commonly reported public health problem in India which can affect the sleep and cause psychosocial problems[53]. It is also a widely common contagious skin disease affecting all domestic animals[54],[55].

Other mite infections

Demodicosis or demodicosis are skin disorders in which increased amounts of demodex mites are seen. Demodicosis was first reported by[56]. Demodex folliculorum and D. brevis are two major mite species found on humans causing a disease “Human demodicosis”, common in India[57]. Severe mite dust allergy leads to human dermatoses, caused by the mites belonging to the Pyemotidae family[58].

Liponyssoides sanguineus, mite of the Dermanyssidae family transmits the disease, rickettsial pox, caused by the pathogen Rickettsia akari. R. akari parasitizes the house-mouse, Mus musculus, and transmits the disease to man[6]. Scrub typhus chiggers and house-mouse mites are found common and associated with rodent zoonosis[22]. Nasobronchial allergic complaints frequently occurred in the dust areas, due to inhalation of mites which are present in the house dust, reported as dust mites. These mites were reported earlier in house dust dating back to the seventeenth century. More than 130 species of mites have so far been isolated from house dust samples all over the world since 1983. The first detailed information on the mites in Indian house dust was made by Rao et al., 1973[59]. Mites of the family Pyroglyphidae, particularly the genus Dermatophagoides are considered to be the most potent allergen in house dust responsible for asthma and other allergic manifestations[60],[61],[62].

Trombiculiasis is an ectoparasitic disease caused directly by the bite of ectoparasite trombiculid mites caused by the salivary secretion of biting chiggers[19] and do not survive due to the adverse host reaction[19].

Trombiculiasis is not common in India. Trombiculosis is the sign and symptoms caused by the bite of the mites as irritation, and active self-grooming in response to intense pruritus.

Ethical statement: Not applicable

  Summary 

In the 1960s and 1970s, scrub typhus was endemic and prevalent in different regions of India. But it disappeared due to the vector control methods adopted. However, in recent years, the resurgence and re-emergence of the disease has occurred, due to the migration of chigger mites from one place to another. Mites were found mainly in the shrubs in hilly and forest terrains. Nowadays this disease is reported from urban areas since rodents carrying the mite are transmitting the disease[63].

In India, scrub typhus was reported first in the Himalayan foothills and then it spread to different parts of south India[44],[64],[65],[66],[67],[68] and north and northeastern parts of the country[69],[70],[71] and some minor cases were reported from Goa, western India[72]. Some localized outbreaks have still occurred and further diagnoses are confirming the prevalence of the disease in India[22]. In the past twenty years, Puducherry has recorded a cluster of 50 cases of scrub typhus during 2006–2008, followed by scrub typhus meningitis in 2011–2012. Numerous publications have shown the outbreak of scrub typhus throughout India[73],[74],[75]. Distribution of a consolidated total and average hospitalized, serological, and outbreak cases of scrub typhus cases in India from 1934 to till date are given in [Table 1]. State- and region-wise hospitalized, serological, and outbreaks reported in India is given in [Table 2].

Table 2: Chronological review of distribution of scrub typhus cases in India

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Historical background of outbreaks in various parts of the country from 1932 onwards with main outbreaks are shown in [Figure 1]A & [Figure 1]B. The increasing trend in the distribution of scrub typhus in Indian states every five years (2001–2020) is given in [Figure 1]C. The number of states and union territories affected by the cases from 2001 to 2020 is shown in [Figure 2].

Figure 1: Scrub typhus outbreaks in India. A. Region wise scrub typhus cases; B. & C. Scrub Typhus outbreaks in India during 1932–2020.

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Figure 2: Scrub typhus affected states and union territories of India (2001–2020)

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  Conclusion 

Scrub typhus is prevalent till now with historical records in India, distributed in all regions in India [Table 2]. Localized outbreak/ clinical cases occur periodically. This is confirmed by serological evidence. Cool climate favors scrub typhus[64]. The proliferation of rodent population increases mite density and there is evidence of increasing scrub typhus cases. In India, historical evidence proved that the Himalayan and sub-Himalayan region climate and vegetations favor scrub typhus via the proliferation of mites and outbreak of the disease[76].

Recent outbreaks of scrub typhus indicate a favorable situation for rodent-vector relationships. Bloodsucking mites (Ornithonyssus sp., Dermanyssus gallinae, Trombiculids, etc.) affect humans. As a vector, by the transfer of pathogenic agents, Trombiculids are more medically important and Oribatid mites act as vectors of herbivore tapeworms. By causing strong allergic reactions in humans, pets and livestock. Dust mites, stored product mites and predisposition to secondary disease (Demodex for Staphylococci)[62], mites are important ectoparasites in human public health.

Worldwide constant climate pattern variations followed by frequent changes experienced by humans in countries like India created more infections within the rodents which harbored the vector species[77]. The present rate of human urbanization, compounded by climate change and inefficient rat control led to a proliferation of rodent-related risks[78]. The changing ecological patterns resulted in agricultural development in rural areas and urban development controlled the composition of rodent populations play a key role in the present condition of mite-borne disease in India[79].

Mite-borne infections are expanding all over the world and the distribution of the vector is shifting and expanding[80]. This work reviews the prevalence of mite-borne infections throughout India and its public health burden which will be a prerequisite for public health authorities to ensure intervention. Thus it is emphasized that there should be a need for the establishment of a permanent mite surveillance system with improved mite-borne disease diagnostics to initiate effective vector control efforts to stop the transmission of mite-borne diseases in the future. Controlling rodent hosts and associated vectors helps to control the outbreak of mite-borne diseases.

Conflict of interest: None

  Acknowledgements 

We are thankful to our Director, ICMR-Vector Control Research Center, Puducherry for providing all the necessary facilities, constant encouragement, guidance, and useful suggestions for undertaking this study. We want to express gratitude to all our departmental colleagues of ICMR-VCRC Field station (erstwhile ICMR-CRME), Madurai, Tamil, Nadu, India.

 

  References 
1.Johnston DE. Acari. In: Parker SP, ed. Synopsis and classification of living organisms. New York: McGraw-Hill; 1982: 111.  
    2.Schauff ME. Mighty mites ubiquitous, inconspicuous, harmful, helpful. Agric Res 2000; 48: 2.  
    3.Hoy MA. The predatory mite Metaseiulus occidentalis: mitey small and mitey large genomes. Bioessays 2009; 31: 581–90.  
    4.Shatrov AB and Kudryashova NI. Taxonomy, life cycles, and the origin of parasitism in trombiculid mites. In: Morand S, Krasnov BR, R P, eds. Micromammals and Macroparasites Part II. Tokyo, Japan: Springer-Verlag 2006:119–140.  
    5.Saha GK. Dust Allergy: Cause & Concern - Indian Perspective. Singapore Springer Science & Business Media 2016: XV, 99.  
    6.Diaz JH. Mites including Chiggers. In: John R. Bennett, Raphael Dolin, Martin J. Blaser, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, pp.1-3904. Amsterdam: Elsevier 2017: 452.  
    7.Watt G and Parola P. Scrub typhus and tropical rickettsioses. Curr Opin Infect Dis 2003; 16: 429–36.  
    8.Chakraborty S and Sarma N. Scrub Typhus: An Emerging Threat. Indian J Dermatol Venereol Leprol 2017; 62: 478–485.  
    9.Traub R and Wisseman CL. The ecology of chigger-borne rickettsiosis (scrub typhus). J Med Entomol 1974; 11: 237–303.  
    10.Schöler A, Maier WA, Kampen H. Multiple environmental factor analysis in habitats of the harvest mite Neotrombicula autumnalis (Acari: Trombiculidae) suggests extraordinarily high euryoecious biology. Exp Appl Acarol 2006; 39: 41–62.  
    11.Clopton RE, Gold RE. Distribution and seasonal and diurnal activity patterns of Eutrombicula alfreddugesi (Acari: Trombiculidae) in a forest edge ecosystem. J Med Entomol 1993; 30: 47–53.  
    12.Sharma P, Rakesh Kakkar, Shilpa N Kaore, Vijay K Yadav, Raj Sharma. Geographical distribution, the effect of season & life cycle of scrub typhus. JK Science 2010; 12(2): 63–64  
    13.Azad AF. Mites of public health importance and their control. Vector control series - WHO/VBC/86.931. Geneva: World Health Organization 1986: 1–52.  
    14.Dong WG, Guo XG, Men XY, Qian TJ, Wu D. Ectoparasites of Rattus steini in areas surrounding Erhai Lake in Yunnan province, China. Int J Parasit Dis 2009; 36: 19–25.  
    15.Mariana A, Vellayan S, Halimaton I, Ho TM. Acariasis on pet Burmese python, Python molurus bivittatus in Malaysia. Asian Pac J Trop Med 2011; 4: 227–8.  
    16.Stan Fernandes S.J, Kulkarni SM. Studies on the Trombiculid Mite Fauna of India. Zoological Survey of India. Occasional paper 2003; 212: 1–539.  
    17.Candasamy S, Ayyanar E, Paily K, Karthikeyan PA, Sundararajan A, Purushothaman J. Abundance & distribution of trombiculid mites & Orientia tsutsugamushi, the vectors & pathogen of scrub typhus in rodents & shrews collected from Puducherry & Tamil Nadu, India. Indian J Med Res 2016; 144: 893–900.  
    18.Brennan JM, Goff ML. Keys to the genera of chiggers of the western hemisphere (acarina: trombiculidae). J Parasitol 1977; 63: 554–66.  
    19.Tamura A, Ohashi N, Urakami H, Miyamura S. Classification of Rickettsia tsutsugamushi in a new genus, Orientia gen. nov., as Orientia tsutsugamushi comb. nov. Int J Syst Bacteriol 1995; 45: 589–91.  
    20.Mullen G and O’Connor B. Mites (Acari). In: Durden L, Mullen G, eds. Medical and Veterinary Entomology. Cambridge Academic Press; 2002: 449–516.  
    21.Tilak R, Kunwar R, Wankhade UB, Tilak VW. Emergence of Schoengastiella ligula as the vector of scrub typhus outbreak in Darjeeling: has Leptotrombidium deliense been replaced?. Indian J Public Health 201; 55: 92–9.  
    22.Sharma S, Raby BA, Hunninghake GM, Soto-Quirós M, Avila L, Murphy AJ et al. Variants in TGFB1, dust mite exposure, and disease severity in children with asthma. Am J Respir Crit Care Med 2009; 179: 356–62.  
    23.Philip Samuel P, Kamarasu K, Govindarajan R, Selvam A, Leo SVJ, Arunachalam N. Preliminary investigation on the prevalence of scrub typhus vectors in Krishnagiri district, Kerala, India. JAdv Zool 2017; 38: 128–132.  
    24.Philip Samuel P, Govindarajan R, Krishnamoorthi R, Krishna Kumari A. A brief note on the Mite and Tick research. Vector Newsletter 2020; 1: 19–21  
    25.Philip Samuel P, Govindarajan R, Krishnamoorthi R, Nagaraj J. Ectoparasites of some wild rodents /shrews captured from Scrub typhus reported areas in Tamil Nadu, India. International Journal of Acarology 2021: 218–221.  
    26.Govindarajan R, Rajamannar V, Krishnamoorthi R, Ashwani Kumar, Philip Samuel P. Distribution pattern of chigger mites in south Tamil Nadu, India. Entomon 2021; 46(3): 247–254.  
    27.Govindarajan R, Rajamannar V, Krishnamoorthi R., Nagaraj J, Ashwani Kumar Philip Samuel P. Species composition of mites (Acari:Trombiculidae, Dermanyssidae, Laelapidae) on pest rodents and shrews in Madurai, India. Halteres 2021; 12: 61–68.  
    28.Philip Samuel P, Govindarajan R, Krishnamoorthi R, Rajamannar V. Ectoparasites diversity on rodents & shrews at scrub typhus endemic Vellore district of Tamil Nadu, India. J Arthropod Borne Dis 2022; 16(1): 51–60  
    29.Philip Samuel P, Govindarajan R, Krishnamoorthi R, Rajamannar V. A study on ectoparasites with special reference to chigger mites on rodents/shrews in scrub typhus endemic areas of Kerala state, India. Entomon 2020; 45: 285–294.  
    30.Philip Samuel P, Govindarajan R, Krishnamoorthi R, Venkatesh A. A rapid protocol for clearing, staining, and mounting of Arthropoda: Trombiculidae, Pediculidae, and Pulicidae. North-West. J. Zool 2021; 17(1): 1–5.  
    31.Jude Prakash JA, Kamarasu K, Philip Samuel P, Govindarajan R, Govindasamy P, Johnson LA, et al. Detection of Orientia tsutsugamushi in Novel Trombiculid Mite Species in Northern Tamil Nadu, India: Use of Targeting the Multicopy traD Gene. Journal of Medical Entomology 2022; 59(2): 693–699.  
    32.Gaur SN. An Indian perspective on dust mites. Indian J Allergy Asthma Immunol 2019; 33: 14–8.  
    33.Podder S, Biswas H, Kumar Saha G. A faunistic survey of house dust mites of Kolkata, West Bengal, India. Acarological Studies 2021; 3(1): 22–31.  
    34.Kelly DJ, Fuerst PA, Ching WM, Richards AL. Scrub typhus: the geographic distribution of phenotypic and genotypic variants of Orientia tsutsugamushi. Clin Infect Dis 2009; 48(3): S203–30.  
    35.Christian CR. A case of typhus due to tick bite. J R Army Med Corps 1932; 59: 445–450  
    36.MacNamara CV. An epidemic of typhus (vector unknown) in the Simla Hills. J R Army Med Corps 1934; 64: 174–186.  
    37.Mehta V, Bhasi A, Panda PK, Gupta P. A coinfection of severe leptospirosis and scrub typhus in Indian Himalayas. J Family Med Prim Care 2019; 8: 3416–3418.  
    38.Boyd JSK. Fevers of typhus group in Inda: Analysis of 110 cases reported in 1934. JR Army Med Corps 1935; 65: 289–305.  
    39.Farner DS, Katsampes CP. Tsutsugamushi disease. US Naval Med Bull 1944; 43: 800–836.  
    40.Bardhan PN. Typhus in the United Provinces of India - Being a contribution to the study of typhus fever. Indian Med Gaz 1944; 79:150–154.  
    41.Mahajan SK, Rolain JM, Sankhyan N, Kaushal RK, Raoult D. Pediatric scrub typhus in Indian Himalayas. Indian J Pediatr 2008; 75: 947–9.  
    42.Sinha P, Gupta S, Dawra R, Rijhawan P. The recent outbreak of scrub typhus in the North-Western part of India. Indian J Med Microbiol 2014; 32.  
    43.Taylor AJ, Paris DH, Newton PN. A Systematic Review of Mortality from Untreated Scrub Typhus (Orientia tsutsugamushi). PLoS Negl Trop Dis 2015; 9: e0003971.  
    44.Isaac R, Varghese GM, Mathai EJM, Joseph I. Scrub typhus: prevalence and diagnostic issues in rural Southern India. Clin Infect Dis 2004; 39: 1395–6.  
    45.Fuller LC. Epidemiology of scabies. Curr Opin Infect Dis 2013; 26: 123–126.  
    46.Bochkov AV, Mironov SV. Phylogeny and systematics of mammal-associated psorptidian mites (Acariformes: Astigmata: Psoroptidia) derived from external morphology. Invert Syst 2011; 25: 22–59.  
    47.Orkin M. Scabies: what is new?. Curr Probl Dermatol 1995; 22: 105-111.  
    48.Karthikeyan K. Crusted scabies. Indian J Dermatol Venereol Leprol 2009; 75: 340–7.  
    49.Behl PN, Taplin D. Eradication of scabies with a single treatment schedule. J Am Acad Dermatol 1985; 12: 117–187.  
    50.Aruna Rastogi. Scabies. New Delhi: The National Health portal, Centre for Health Informatics (CHI), National Institute of Health and Family Welfare (NIHFW), Govt. of India; 2017. Alexander JOD. Berlin Springer-Verlag 1984: 50–5.  
    51.Alexander JOD. Arthropods and skin. Berlin: Springer-Verlag; 1984: 50–5.  
    52.Larry GA, Marjorie SM. A review of Sarcoptes scabiei: past, present, and future. Parasit Vectors 2017; 10: 297.  
    53.Ashok Nair P, Vora RV, Jivani NB, Gandhi SS. A Study of Clinical Profile and Quality of Life in Patients with Scabies at a Rural Tertiary Care Centre. J Clin Diagn Res 2016; 10(10): WC01–WC05.  
    54.Chhabra MB, Pathak KML. Sarcoptic mange in domestic animals and human scabies in India. Vet. Parasitol 2011; 25(1): 1–10.  
    55.Gupta DK, Singh RP, Singh AK, Agarwal AK, Kumar A, Gava U. Study of prevalence and determinants associated with scabies in rural area of Bareilly. Indian J Comm Health 2021; 33(1): 169–174.  
    56.Ayres S. Pityriasis folliculorum (Demodex). Arch Dermatol Syphilol 1930; 21: 19–24.  
    57.Rather PA, Hassan I. Human demodex mite: the versatile mite of dermatological importance. Indian J Dermatol 2014; 59: 60–6.  
    58.Nath R, Saikia L, Choudhury M, Mahanta J. Dermatitis due to straw itch mite in Assam. Indian J Dermatol Venereol Leprol 2007; 52: 199–200.  
    59.Krishna Rao NS, Khudus N, Channa Basavanna GP. Pyroglyphid mites in man and his surroundings. Curr Sci 1973; 42: 33.  
    60.Pepys J, Chan M, Hargreave FB. Mites and house-dust allergy. Lancet 1968; 7555: 1270–1272.  
    61.Saha GK. House dust mite sensitivity among rural and urban asthmatics of West Bengal, India: A comparison. Aerobiologia 1997; 13: 269–273.  
    62.Laskar A, Shivali S, Acharya A. 2015. Scrub Typhus: Reemerging Public Health Problem in India. J Commun Dis 2015; 47(3): 19–25.  
    63.Mathai E, Rolain JM, Verghese GM, Abraham OC, Mathai D, Mathai M et al. Outbreak of scrub typhus in southern India during the cooler months. Ann N Y Acad Sc 2003; 990: 359–64.  
    64.