Detection of antibodies in sera of weaned pigs after contact infection with Sarcoptes scabiei var. suis and after treatment with an antiparasitic agent by three different indirect ELISAs

Proteomic analysis of plasma to identify novel biomarkers for intra-amniotic infection and/or inflammation in preterm premature rupture of membranes

To identify potential plasma biomarkers associated with microbial invasion of the amniotic cavity (MIAC) and/or intraamniotic inflammation (IAI) in women with preterm premature rupture of membranes (PPROM). This retrospective cohort study included 182 singleton pregnant women with PPROM (23-33 weeks) who underwent amniocentesis. Plasma samples; all subjects were chosen from these participants and were analyzed using label-free liquid chromatography-tandem mass spectrometry for proteome profiling using a nested case-control study design (cases with MIAC/IAI vs. non-MIAC/IAI controls [n = 9 each]). Three identified target molecules for MIAC/IAI were further verified by ELISA in the study cohort (n = 182). Shotgun proteomic analysis revealed 17 differentially expressed proteins (P < 0.05) in the plasma of MIAC/IAI cases. In particular, the levels of FCGR3A and haptoglobin, but not LRP1, were found to be increased in the plasma of patients with MIAC, IAI, and both MIAC/IAI compared with those without these conditions. Moreover, these differences remained significant after adjusting for gestational age at sampling. The area under the curves of plasma FCGR3A and haptoglobin ranged within 0.59-0.65 with respect to each of the three outcome measures. Plasma FCGR3A and haptoglobin were identified as potential independent biomarkers for less-invasively detecting MIAC/IAI in women with PPROM.

Comparative analysis of the allergenic characteristics and serodiagnostic potential of recombinant chitinase-like protein-5 and -12 from Sarcoptes scabiei

Background

Scabies is caused by burrowing of the mite Sarcoptes scabiei into the stratum corneum. Currently, diagnosis via routine skin scraping is very difficult, and information on the allergenic identification of S. scabiei remains limited.

Methods

We performed comparative analysis of the serological diagnostic potential of recombinant S. scabiei chitinase-like protein-5 (rSsCLP5) and recombinant S. scabiei chitinase-like protein-12 (rSsCLP12) by measuring the levels of serum-specific IgG and IgE antibodies (Abs) as diagnostic markers. In addition, the allergenic characteristics of rSsCLP5 and rSsCLP12 were evaluated using IgE-binding experiments and skin tests.

Results

The IgE Abs-based indirect enzyme-linked immunosorbent assay (ELISA) methods showed high sensitivity and specificity: the rSsCLP5-based assay had 93.5% sensitivity and 94.4% specificity; the rSsCLP12-based assay had 100% sensitivity and 98.1% specificity. The specific IgE Abs in infested mouse sera could bind rSsCLP5 and rSsCLP12. In skin tests, rabbits in the rSsCLP5 and rSsCLP12 groups and positive control (histamine) groups exhibited allergic reactions. Most test sites in the rSsCLP12 group had edema, bleeding spots, and even ulcers or scabs, but such allergy symptoms were rare in the rSsCLP5 group. Moreover, the allergic history rabbit group had more severe allergic reactions and lower levels of IgE Abs compared to the healthy rabbit group in the same protein group.

Conclusions

These findings validate the use of IgE Abs to rSsCLP5 and rSsCLP12 as potentially useful markers for diagnosing scabies. Moreover, both rSsCLP5 and rSsCLP12 have allergenic properties, and the potential allergen rSsCLP12 is a stronger allergen than rSsCLP5.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04654-0.

Primary skin diseases and cutaneous manifestations of systemic diseases in swine

ABSTRACT: Skin diseases in pigs can negatively impact the production. They cause losses related to the death of the affected pigs, to the cost with the treatment, growth retardation and condemnations in the slaughterhouses. This study was developed to determine the frequency and describe the histopathological findings of skin diseases in pigs in different age groups through a retrospective study from 2006 to 2018. A total of 154 conclusive cases were analyzed, including skin restricted diseases (allergic dermatitis, exudative epidermitis, vesicular dermatitis, pityriasis rosea, swinepox, follicular cyst, papilloma and scrotal hemangioma) or skin lesions secondary to systemic diseases (erysipelas, porcine dermatitis and nephropathy syndrome (PDNS), bacterial septicemia and multiple hemorrhages without definite cause). The skin lesions were classified as bacterial (46.1%), viral (26.6%), allergic (12.3%), neoplastic (1.3%) and others (13.6%). Swine erysipelas was the most frequent diagnosis (47/154), followed by PDNS (23/154), allergic dermatitis (19/154) and exudative epidermitis (15/154). Vesicular dermatitis (9/154), pityriasis rosea (9/154), septicemia with cutaneous manifestations (9/154), swinepox (9/154) and multiple hemorrhages without definite cause (7/154) were also observed. Follicular cyst (3/154), hyperkeratosis without definite cause (2/154), papilloma (1/154), and scrotal hemangioma (1/154) were less frequently described. Of the conclusive diagnosis, age was reported in 138 cases, with the highest frequency of skin lesions observed at the inspection process during slaughter (56/138).

An Antibody Persistent and Protective Two rSsCLP-Based Subunit Cocktail Vaccine against Sarcoptes scabiei in a Rabbit Model

Scabies is a highly contagious disease caused by Sarcoptes scabiei which burrows into stratum corneum of host's skin. In this study, after optimizing vaccination schedule, a vaccination trial is comprised of three test groups of rabbits (n = 10/group) by immunization with (1) rSsCLP5; (2) rSsCLP12; or (3) a mixture of rSsCLP5 and rSsCLP12, three biological replicates groups (n = 10/group) and three control groups (n = 10/group). Levels of specific IgG, total IgE and cytokines in sera were detected and histopathologically analyzed as indicators of vaccine effects. The results showed that 85% (17/20) of rabbits exhibited no detectable skin lesions of S. scabiei infestation in mixed protein groups compared to single protein groups with 75% (15/20) and 70% (14/20), respectively. Moreover, the deworming rates of mixed groups are increased by 10%-20% compared with that of single groups. Each of six groups immunized with rSsCLP displayed significant increases of specific IgG, total IgE, IL-10, and TNF-α. The degree of skin damage in test groups also significantly lower than that of control groups. Thus, purified rSsCLP5 and rSsCLP12 subunit cocktail vaccine induced robust immune protection and could significantly decrease mite populations to reduce the direct transmission between rabbits.

Sarcoptes infestation in two miniature pigs with zoonotic transmission - a case report

Background

Scabies is a contagious skin disease rarely described in miniature pigs. To the best of the authors’ knowledge, a zoonotic transfer from infected pet pigs to humans has not been reported previously.

Case presentation

This case report describes the infestation with Sarcoptes scabiei mites in two miniature pigs presenting with unusual clinical signs, and disease transmission to a child.

Two 7-month-old male castrated miniature pig siblings were examined. Both had developed skin lesions, one animal was presented for neurological signs and emaciation. They were housed together in an indoor- and outdoor enclosure. Dermatological examination revealed a dull, greasy coat with generalized hypotrichosis and multifocal erythema. Microscopic examination of skin scrapings, impression smears of affected skin and ear swabs revealed high numbers of Sarcoptes mites in both animals as well as bacterial overgrowth. A subcutaneous injection of ivermectin 0.3 mg/kg was administered to both animals and repeated after 2 weeks. Both miniature pigs received subcutaneous injections with butafosfan and cyanocobalamin, were washed with a 3% chlorhexidine shampoo and were fed on a well-balanced diet. Pig enclosures were cleaned. The infested child was examined by a physician and an antipruritic cream was prescribed. Both miniature pigs and the child went into clinical remission after treatment.

Conclusion

Sarcoptic mange is rare or even eradicated in commercial pig farming in many countries but miniature pigs may represent a niche for Sarcoptes scabiei infections. This case report indicates that miniature pigs kept as pets can efficiently transmit zoonotic disease to humans. In addition, these animals may represent a niche for Sarcoptes scabiei infestation in countries where sarcoptic mange in commercial pig farms has been eradicated and could therefore pose, a hazard for specific pathogen free farms.

Expression and characterisation of a Sarcoptes scabiei protein tyrosine kinase as a potential antigen for scabies diagnosis

Scabies is a disease that harms humans and other animals that is caused by the itch mite Sarcoptes scabiei burrowing into the stratum corneum of the skin. In the early stages of scabies, symptoms are often subclinical and there are no effective diagnostic methods. Herein, we cloned, expressed and characterised an S. scabiei protein tyrosine kinase (SsPTK) and evaluated its diagnostic value as a recombinant antigen in rabbit during the early stages of Sarcoptes infestation. The SsPTK protein is ~30 kDa, lacks a signal peptide, and shares high homology with a PTK from the rabbit ear mite Psoroptes ovis cuniculi. The protein was widely distributed at the front end of mites, particularly in the chewing mouthparts and legs. Indirect ELISA using recombinant SsPTK showed good diagnostic value, with 95.2% (40/42) sensitivity and 94.1% (48/51) specificity for detecting anti-PTK antibody in serum samples from naturally-infested rabbits. More importantly, PTK ELISA could diagnose infection in the early stages (infestation for 1 week) with an accuracy of 100% (24/24). SsPTK therefore shows potential as a sensitive antigen for the early diagnosis of parasitic mite infestation.

A review of Sarcoptes scabiei: past, present and future

The disease scabies is one of the earliest diseases of humans for which the cause was known. It is caused by the mite, Sarcoptes scabiei, that burrows in the epidermis of the skin of humans and many other mammals. This mite was previously known as Acarus scabiei DeGeer, 1778 before the genus Sarcoptes was established (Latreille 1802) and it became S. scabiei. Research during the last 40 years has tremendously increased insight into the mite’s biology, parasite-host interactions, and the mechanisms it uses to evade the host’s defenses. This review highlights some of the major advancements of our knowledge of the mite’s biology, genome, proteome, and immunomodulating abilities all of which provide a basis for control of the disease. Advances toward the development of a diagnostic blood test to detect a scabies infection and a vaccine to protect susceptible populations from becoming infected, or at least limiting the transmission of the disease, are also presented.

Preclinical Study of Single-Dose Moxidectin, a New Oral Treatment for Scabies: Efficacy, Safety, and Pharmacokinetics Compared to Two-Dose Ivermectin in a Porcine Model

Background

Scabies is one of the commonest dermatological conditions globally; however it is a largely underexplored and truly neglected infectious disease. Foremost, improvement in the management of this public health burden is imperative. Current treatments with topical agents and/or oral ivermectin (IVM) are insufficient and drug resistance is emerging. Moxidectin (MOX), with more advantageous pharmacological profiles may be a promising alternative.

Methodology/Principal Findings

Using a porcine scabies model, 12 pigs were randomly assigned to receive orally either MOX (0.3 mg/kg once), IVM (0.2 mg/kg twice) or no treatment. We evaluated treatment efficacies by assessing mite count, clinical lesions, pruritus and ELISA-determined anti-S. scabiei IgG antibodies reductions. Plasma and skin pharmacokinetic profiles were determined. At day 14 post-treatment, all four MOX-treated but only two IVM-treated pigs were mite-free. MOX efficacy was 100% and remained unchanged until study-end (D47), compared to 62% (range 26–100%) for IVM, with one IVM-treated pig remaining infected until D47. Clinical scabies lesions, pruritus and anti-S. scabiei IgG antibodies had completely disappeared in all MOX-treated but only 75% of IVM-treated pigs. MOX persisted ~9 times longer than IVM in plasma and skin, thereby covering the mite’s entire life cycle and enabling long-lasting efficacy.

Conclusions/Significance

Our data demonstrate that oral single-dose MOX was more effective than two consecutive IVM-doses, supporting MOX as potential therapeutic approach for scabies.

Scabies caused by the Sarcoptes scabiei mite affects many people worldwide and has been recently recognized by the WHO as a truly neglected tropical disease. Currently available treatments are insufficient to overcome this insidious disease and its co-morbidities for example impetigo, rheumatic heart disease and post-streptococcal glomerulonephritis. Treatment management is a major issue, as problems with compliance as well as mite resistance to current drugs are reported. Data have accumulated indicating that moxidectin could be a genuine new candidate drug for sustainable scabies control. To provide proof of concept, we utilized an experimental scabies pig model that closely resembles the human route of scabies infection. We demonstrated that a single moxidectin dose, when compared with the currently recommended two-doses ivermectin treatment routine, achieved a better and faster acaricidal efficacy. Importantly, the skin half-life of moxidectin is longer, potentially covering the entire mite life cycle. Our baseline data demonstrate in principle the potential and feasibility of moxidectin treatment for scabies, thereby enabling the move into larger high-powered efficacy and dose ranging studies in human populations. Moxidectin could indeed play a game-changing role in scabies control and has the potential to accelerate the steps towards elimination of this insidious disease.

Sarcoptic mange infestation in pigs: an overview

Sarcoptic mange infestation in pigs is caused by Sarcoptes scabiei var. suis. It is the most common mange infestation of pigs. The parasite is distributed worldwide. Pig owners are generally concerned about the internal parasitic infections and ignored the external parasitic infestations. But the external parasitic infestation with S. scabiei var. suis has economic significance as it causes morbidity, mortality, decreased fertility and feed conversion ratio in pigs. Keeping in view of importance of S. scabies var. suis infestation in pigs, this communication discussed about the present and past research works done on S. scabies var. suis infestation in pigs, particularly its prevalence, life cycle, pathological lesions, clinical symptoms, haematobiochemical changes, diagnosis, treatment and control, to have an idea about this infestation at a glance. It has been concluded that the research work done on sarcoptic mange infestation in pigs in India is less in comparison to other countries. It may be due to its consideration as a neglected parasite or due to it's under report. Organization of awareness programs for the farmers by extension personalities or other authorities might be able to save the farmers from economic losses due to this infestation.

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

Despite the availability of effective treatments, Sarcoptes scabiei remains a major health problem in the pig industry. Unsuccessful control of the disease is often due to the lack of reliable detection methods, with current tests relying on skin scrapings and crude antigen ELISAs. A previous analysis of antigens in pig skin scrapings reported that anti-transferrin antibodies were present in S. scabiei infected animals and that this finding might be considered as a useful diagnostic tool. This paper confirms IgG autoantibodies against transferrin, including the first report of IgM autoantibodies, in both naturally and experimentally infected pigs using ELISA and dot blot assays. Autoantibodies were also detected in pigs to ferritin and to a lesser extent lactoferrin. Immunoblotting confirmed the presence of IgG and IgM autoantibodies in mange positive pigs, as well as IgM antibodies to transferrin and albumin in mange negative pigs. These findings suggest the presence of natural autoantibodies to transferrin and albumin in pigs. The development of the IgG autoimmune response may either be a host mechanism for limiting iron to the mite via antibody mediated clearance, the result of host exposure to mite iron-binding homologues or because of a mite-induced antigenic change to host transferrin. Further investigation into the formation of these autoantibodies may provide insights into the importance of iron in scabies infections and the development and perseverance of S. scabiei infections in pigs. The specificity and sensitivity of the anti-transferrin response reinforces its potential in the diagnosis of scabies in pigs.

Variable performance of a human derived Sarcoptes scabiei recombinant antigen ELISA in swine mange diagnosis

The performance of an indirect ELISA test based on Sarcoptes scabiei var hominis recombinant antigen Ssλ20ΔB3 (rec-ELISA), to diagnose pig mange was investigated in 15 experimentally infected and non-infected pigs and 692 commercial pigs from 16 herds in southeast Spain. These latter animals included 6-7 month old fatteners (13 herds), 11-12 month old replacement sows (1 herd) and ≥24 month old breeding sows (7 herds). All pigs were examined for mites in ear skin scrapings and the presence of S. scabiei-associated macroscopic dermatitis; moreover, fatteners were also tested for antibodies against porcine viruses including: Aujeszky disease virus (ADV), swine influenza virus (SIV), type 2 porcine circovirus (PCV2) and porcine respiratory and reproductive syndrome virus (PRRSV). S. scabiei and chronic hyperkeratotic dermatitis were detected in breeding sows from 6 herds. Mite prevalence in other pigs was 83% in replacement sows, 0% in 7 fattener's herds and 3-82% in other fattener's herds. All fattener herds had pigs with acute hypersensitivity dermatitis and the percentage of affected pigs and lesion area was significantly greater in S. scabiei infected ones. Rec-ELISA relative optical densities (RODs) were greater in older than in young pigs, as well as in infected compared to non-infected pigs. However, RODs differed significantly between infected individuals, regardless of age and origin (commercial or experimental) and the herd prevalence of S. scabiei. Low repeatability between ELISA microtiter plates, suggesting variable specific antibody binding to antigen, are likely partly responsible for ROD variation. Other potential causes of variation were examined in fatteners using random effects logistic regression analysis, after defining a seropositivity threshold value with receiver-operating characteristics (ROC) analysis. The logistic model indicated that seropositivity was associated with large dermatitis areas and with the only herd with low PCV2 seroprevalence. Pigs with more extensive dermatitis may have older infections and more rec-ELISA detectable antibodies. The possibility that PCV2, a recognized immunosupressor, depresses antibody production against S. scabiei infection merits further attention. In summary, results indicate some potential of the studied rec-ELISA as a complementary tool for herd-level swine mange diagnosis, and that work to reduce internal and external sources of assay variation is essential.

Characterization and evaluation of a Sarcoptes scabiei allergen as a candidate vaccine

Background

Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide disease affecting both humans and animals. Here we report the molecular characterization and evaluation of a recombinant S. scabiei tropomyosin (SsTm) protein in a vaccination trial in rabbits.

Methods

The full-length cDNA was cloned in a bacterial pET vector, and the recombinant protein was expressed in BL21 (DE3) cells and purified. Using specific rabbit antiserum, tropomyosin was localized immunohistochemically in mite tissue sections. Vaccination trials with the recombiant SsTm was carried out in New Zealand rabbits.

Results

The full-length open reading frame (ORF) of the 852 bp cloned gene from S. scabiei encodes a 32.9 kDa protein. The amino acid sequence showed 98.94%, 97.89% and 98.59% homology to Dermatophagoides farina and Dermatophagoides pteronyssinus group 10 allergens and Psoroptes ovis tropomyosin, respectively. Tropomyosin was localized immunohistochemically in mite tissue sections mainly in the mouthparts, legs and integument of the epidermis. The predicted cross-reactivity of SsTm indicated that it is an allergenic protein. While vaccination with the recombiant SsTm resulted in high levels of specific IgG (P < 0.01), a low IgE antibody response and no significant protection against S. scabiei challenge were observed. After challenge, specific IgG levels remained significantly higher than the control (P < 0.01), while changes of total IgE levels were not significant (P > 0.05). However, the lesion areas in the vaccination group decreased at the end of the experiment compared with controls.

Conclusions

Although vaccination with recombinant SsTm did not efficiently control sarcoptic mange in rabbits, the immunogenic properties of tropomyosin suggest it may be developed as a vaccine with alternative adjuvants or delivery methods.

Characterisation of recombinant immunoreactive antigens of the scab mite Sarcoptes scabiei

Sarcoptic mange (or scabies) is an important skin disease which can affect a variety of species including humans, cattle, goats, sheep, horses, pigs, rabbits, and dogs. Approximately 300 million people are affected worldwide and in lifestock animals the infestation may lead to substantial economic losses caused by depression in growth and feed conversion rates. Diagnosis of Sarcoptes infestation is difficult and only a few serological tests have been developed using whole mite antigen for diagnosis of mange in animals. Here we describe the isolation and characterisation of cDNAs of several immunoreactive clones and their recombinant expression in Escherichia coli. Three of the proteins contain repetitive sequences which suggests that they might be involved in immune evasion. The application of these antigens in serodiagnosis and the suitability for diagnosis is discussed.

In vivo evidence that Sarcoptes scabiei (Acari: Sarcoptidae) is the source of molecules that modulate splenic gene expression

The clinical signs of a Sarcoptes scabiei (De Geer) (Acari: Sarcoptidae) infestation are initially delayed, which suggests that the mites can depress the immune/inflammatory response. The purpose of this study was to investigate the modulatory properties of scabies mites in vivo at the gene expression level in a secondary lymphoid organ that is involved in initiating an immune response to the parasite. We found that substances from scabies mites influenced the expression of mRNA for molecules that participate in the sequestering of lymphocytes in the periarteriolar lymphoid sheath, primary follicle, and marginal zone of the spleen. Mice exposed to live scabies mites exhibited decreased mRNA expression for the adhesion molecules intercellular adhesion molecule (ICAM)-1, ICAM-2 and L-selectin; the cytokines tumor necrosis factor (TNF)alpha and CCL5; and the receptors for several other cytokines including TNF and interferon gamma. In addition, exposure to live mites or vaccination with a scabies extract resulted in reduced expression of mRNA for B7-2, CD40, CD4, CD8, and CD45, thereby potentially reducing the physical interactions between B cells and T-helper (Th)2 helper cells, between Th1 and Tc cells, and between T-helper cells and antigen-presenting cells, thus depressing their function in response to thymus-dependent antigen. Live scabies mites also depressed expression of toll-like receptors 2, 4, and 6. In conclusion, our results indicate that live mites produce substances that can down-regulate expression of adhesion molecules, cytokines, chemokines, chemokine receptors, and lymphocyte surface molecules involved in leukocyte sequestering and the interaction of B and T cells during activation of an immune response in the spleen.

Immunoblot analysis of IgG antibody response to Sarcoptes scabiei in swine

This study was performed to determine the frequencies and specificities of IgG antibodies binding to component of Sarcoptes scabiei extracts in swine with hypersensitive and chronic mange. The hypersensitive form is characterised by pruritus and the presence of small red papules over the flanks and belly. The chronic form is characterised by crusts, which contain large numbers of mites and are attached to the skin; the lesions are most commonly found on the internal pinna extending into the auditory canal. S. scabiei mite extract was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with subsequent immunoblotting. IgG-binding proteins were detected with individual sera from 30 hypersensitive and 21 chronically infected pigs; eight "Specific Pathogen Free" pigs were used as negative controls. Seven protein bands with molecular weights ranging from >220 to 30 Kilodalton (KDD) (>220, 218, 110, 80, 66, 52, 36 KDD) strongly bound with IgG antibodies; five out of these seven components (218, 110, 80, 66, 52 KDD) bound also with sera from negative pigs. There is a statistically significant difference in the antigenic recognition spectra between hypersensitive and chronically infected pigs; component of >220 KDD is more frequently recognized by chronically infected pigs (P=0.0006, chi(2)=11.74), in contrast component of 36 KDD is more frequently recognized by hypersensitive pigs (P=0.001, chi(2)=10). Our results clearly indicate there is a difference in the reactivity to antigenic peptides/proteins of S. scabiei mite between hypersensitive and chronically infected pigs, and revealed that only two antigens may be considered S. scabiei-specific and used for diagnostic purposes in swine.