Autoantibodies to iron-binding proteins in pigs infested with Sarcoptes scabiei

Immune mechanisms in human Sarcoptes scabiei (Acari: Sarcoptidae) infestations

Scabies is a parasitic infestation of human and animal skin caused by different strains of the itch mite, Sarcoptes scabiei. The World Health Organization (WHO) has declared scabies in human as a neglected tropical disease, and today over 200 million people worldwide are affected. The two most commonly reported clinical manifestation of the condition are ordinary (OS) and crusted scabies (CS). CS, which can lead to fatal consequences due to secondary bacterial infections, is mostly observed in immunocompromised subjects but can also, although rarely, be detected in immunocompetent individuals. Innate and adaptive immune system components are involved in protection and pathogenesis of scabies, although with some differences between OS and CS. While the cutaneous immune response is dominated by CD4⁺ T-cells in OS, it is mainly mediated by CD8⁺ T-cells in CS. The two clinical conditions also differ in CD4⁺ T-cell-mediated immune responses with mixed T_H 1/T_H 2 (protective) and T_H 2/T_H 17 (non-protective) immunoprofiles in OS and CS, respectively. Moreover, the development of CS is associated with early immunosuppression that is followed by deleterious immune response to uncontrolled mite proliferation. However, the immune response to scabies still needs further attention due to inconsistent results in the literature. The aim of this study is to attract more attention to this area by summarizing the current literature on innate and adaptive immune responses triggered against S. scabiei mites.

Porcine scabies induces marked apoptosis, increased pro-inflammatory cytokines IL-1, TNF-α and shedding of ICAM-1

BACKGROUND

Scabies is one of the leading causes of morbidity in pigs worldwide. Limited data are available regarding the role of immune reactions in the development of porcine scabies.

MATERIALS AND METHODS

The aim of this study was to investigate key pro-inflammatory cytokines (IL-1, TNF-α), soluble variant of adhesion molecule ICAM-1 and mite-mediated apoptosis of peripheral leukocytes in 20 pigs with scabies, in addition to 10 healthy controls. The pigs with at least three typical clinical signs and found positive for Sarcoptes scabiei var. suis in microscopy were recruited for the present study.

RESULTS

IL-1 acted as the major pro-inflammatory cytokine as serum IL-1 concentrations showed significantly (p < .05) higher levels (7-fold increase) in cases than in controls. The minor cytokine TNF-α was 4-fold higher during scabies, and its mean serum concentration was significantly increased (p < .05) in cases when compared to healthy controls. Soluble ICAM-1 levels were significantly higher (p < .05) in all the pigs of infested group compared with the controls. The percentage of apoptotic and necrotic leukocytes was found to be significantly higher (p < .05) in scabies positive pigs as compared to the healthy controls.

CONCLUSION

It is concluded that systemic elevation in pro-inflammatory cytokines IL-1 and TNF-α, shedding of soluble ICAM-1 variant in peripheral blood and increased rate of host-cell apoptosis in peripheral leukocytes might be implicated in the immunopathology of naturally acquired porcine scabies.

Transcriptome-microRNA analysis of Sarcoptes scabiei and host immune response

Scabies is a parasitic disease, caused by the mite Sarcoptes scabiei, and is considered one of the top 50 epidemic diseases and one the most common human skin disease, worldwide. Allergic dermatitis, including an intense itch, is a common symptom, however diagnosis is difficult and there is currently no effective vaccine. The goal of this study was to examine the immune interaction mechanism of both S. scabiei and infected hosts. mRNA-seq and microRNA-seq were conducted on the S. scabiei mite and on infected and uninfected hosts. We focused on differential expression of unigenes and microRNAs, as well as the real targets of unigenes in enriched immune signaling pathways. S. scabiei enhanced host immune function and decreased metabolism after infection, while the immune response of the host inhibited S. scabiei proliferation and metabolism signaling pathways. Differentially expressed unigenes of S. scabiei were enriched in the JAK-STAT signaling pathway and the Toll-like receptor signaling pathway. The differential expression analysis indicated that microRNAs of S. scabiei and hosts have major roles in regulating immune interactions between parasites and hosts.

Parasitic mites of medical and veterinary importance--is there a common research agenda?

There are an estimated 0.5-1 million mite species on earth. Among the many mites that are known to affect humans and animals, only a subset are parasitic but these can cause significant disease. We aim here to provide an overview of the most recent work in this field in order to identify common biological features of these parasites and to inform common strategies for future research. There is a critical need for diagnostic tools to allow for better surveillance and for drugs tailored specifically to the respective parasites. Multi-'omics' approaches represent a logical and timely strategy to identify the appropriate mite molecules. Recent advances in sequencing technology enable us to generate de novo genome sequence data, even from limited DNA resources. Consequently, the field of mite genomics has recently emerged and will now rapidly expand, which is a particular advantage for parasitic mites that cannot be cultured in vitro. Investigations of the microbiota associated with mites will elucidate the link between parasites and pathogens, and define the role of the mite in transmission and pathogenesis. The databases generated will provide the crucial knowledge essential to design novel diagnostic tools, control measures, prophylaxes, drugs and immunotherapies against the mites and associated secondary infections.