Primary Infestations Research Articles

Receptor for Advanced Glycation End Product (RAGE) Modulates Inflammation During Feeding of the Hard Tick, Haemaphysalis longicornis in Mice.

Ticks are notorious blood-sucking ectoparasites that affect both humans and animals. They serve as a unique vector of various deadly diseases. Here, we have shown the roles of the receptor for advanced glycation end products (RAGE) during repeated infestations by the tick Haemaphysalis longicornis using RAGE-/- mice. In primary infestation, a large blood pool developed, which was flooded with numerous RBCs, especially during the rapid feeding phase of the tick both in wild-type (wt) and RAGE-/- mice. Very few inflammatory cells were detected around the zones of haemorrhage in the primary infestations. However, the number of inflammatory cells gradually increased in the subsequent tick infestations, and during the third infestations, the number of inflammatory cells reached to the highest level (350.3 ± 16.8 cells/focus). The site of attachment was totally occupied by the inflammatory cells in wt mice, whereas very few cells were detected at the ticks' biting sites in RAGE-/- mice. RAGE was highly expressed during the third infestation in wt mice. In the third infestation, infiltration of CD44+ lymphocytes, eosinophils and expression of S100A8 and S100B significantly increased at the biting sites of ticks in wt, but not in RAGE-/- mice. In addition, peripheral eosinophil counts significantly increased in wt but not in RAGE-/- mice. Taken together, our study revealed that RAGE-mediated inflammation and eosinophils played crucial roles in the tick-induced inflammatory reactions.

From “cutaneous anthrax” to “primary delusional infestation”

IntroductionPrimary delusional infestation is a rare psychiatric condition in which patients mistakenly believe that their skin or other body parts are infested by small, living organisms, despite the fact that no organisms can be found upon investigation. The delusion occurs concurrently with abnormal cutaneous sensations. Therefore, they typically have a history of prior negative evaluations by dermatologists and general practice physicians. In addition, patients may have also received repeated courses of dermatologic and anti-infective therapies, despite the lack of an objective diagnosis.ObjectivesTo describe the clinical case of a patient who suffered from an undiagnosed primary delusional infestation for 12 years.MethodsDescription of a clinical case and a non-systematic review of the literature.ResultsWe describe the clinical case of a 65-year-old woman who spent 12 years being evaluated by multiple medical and surgical specialties for the following complaint: “sensation of something moving beneath the skin.” At the onset of the complaint, the patient believed that this “strange sensation” was due to a recent tooth procedure. However, as she felt the discomfort not improving, she believed it to be a consequence of a cutaneous anthrax infection. Thus, the patient started using tweezers to grasp the living organism that was bothering her and that behavior caused intense scaring in her face. Meanwhile, the patient was also submitted to 3 cutaneous biopsies (prescribed by a dermatologist) that refuted the hypothesis of any living organism underneath her skin. In addition, the patient was prescribed sertraline, bromazepam and lorazepam that, although improved her sleep and anxiety levels, were inefficient to treat the root of her suffering. Finally, after 12 years of dispersed medical follow-up, this patient was evaluated by a new psychiatrist and prescribed paliperidone that rapidly made the agonizing “strange sensation” disappear.ConclusionsEven though primary delusional infestations are a rare psychiatric diagnosis, all medical doctors should consider it when their patients report bothersome dermatologic complaints associated with the belief of infestation and negative diagnostic examinations. It is incredibly important to consider this diagnostic, as the early treatment of this entity might prevent the patient from undergoing multiple years of suffering and discomfort.Disclosure of InterestNone Declared

Immune and biochemical responses in skin differ between bovine hosts genetically susceptible and resistant to the cattle tick Rhipicephalus microplus

BackgroundTicks attach to and penetrate their hosts’ skin and inactivate multiple components of host responses in order to acquire a blood meal. Infestation loads with the cattle tick, Rhipicephalus microplus, are heritable: some breeds carry high loads of reproductively successful ticks, whereas in others, few ticks feed and reproduce efficiently.MethodsIn order to elucidate the mechanisms that result in the different outcomes of infestations with cattle ticks, we examined global gene expression and inflammation induced by tick bites in skins from one resistant and one susceptible breed of cattle that underwent primary infestations with larvae and nymphs of R. microplus. We also examined the expression profiles of genes encoding secreted tick proteins that mediate parasitism in larvae and nymphs feeding on these breeds.ResultsFunctional analyses of differentially expressed genes in the skin suggest that allergic contact-like dermatitis develops with ensuing production of IL-6, CXCL-8 and CCL-2 and is sustained by HMGB1, ISG15 and PKR, leading to expression of pro-inflammatory chemokines and cytokines that recruit granulocytes and T lymphocytes. Importantly, this response is delayed in susceptible hosts. Histopathological analyses of infested skins showed inflammatory reactions surrounding tick cement cones that enable attachment in both breeds, but in genetically tick-resistant bovines they destabilized the cone. The transcription data provided insights into tick-mediated activation of basophils, which have previously been shown to be a key to host resistance in model systems. Skin from tick-susceptible bovines expressed more transcripts encoding enzymes that detoxify tissues. Interestingly, these enzymes also produce volatile odoriferous compounds and, accordingly, skin rubbings from tick-susceptible bovines attracted significantly more tick larvae than rubbings from resistant hosts. Moreover, transcripts encoding secreted modulatory molecules by the tick were significantly more abundant in larval and in nymphal salivary glands from ticks feeding on susceptible bovines.ConclusionsCompared with tick-susceptible hosts, genes encoding enzymes producing volatile compounds exhibit significantly lower expression in resistant hosts, which may render them less attractive to larvae; resistant hosts expose ticks to an earlier inflammatory response, which in ticks is associated with significantly lower expression of genes encoding salivary proteins that suppress host immunity, inflammation and coagulation.

Murine cutaneous responses to the rocky mountain spotted fever vector, Dermacentor andersoni, feeding.

Tick salivary glands produce complex cocktails of bioactive molecules that facilitate blood feeding and pathogen transmission by modulating host hemostasis, pain/itch responses, wound healing, and both innate and adaptive immunity. In this study, cutaneous responses at Dermacentor andersoni bite-sites were analyzed using Affymetrix mouse genome arrays and histopathology at 12, 48, 96 and 120 h post- infestation (hpi) during primary infestations and 120 hpi during secondary infestations. The microarray data suggests: (1) chemotaxis of neutrophils, monocytes, and other cell types; (2) production and scavenging of reactive oxygen species; and, (3) keratin- based wound healing responses. Histological analysis supported the microarray findings. At 12 hpi, a mild inflammatory infiltrate was present in the dermis, especially concentrated at the junction between dermal connective tissue and underlying adipose tissue. A small lesion was located immediately under the hypostome and likely represents the feeding “pool.” Surprisingly, at 48 hpi, the number of inflammatory cells had not increased from 12 hpi, perhaps mirroring the reduction in gene expression seen at this time point. The feeding lesion is very well defined, and extravasated erythrocytes are readily evident around the hypostome. By 96 hpi, the inflammatory infiltrate has increased dramatically and the feeding lesion appears to have moved deeper into the dermis. At 120 hpi, most of the changes at 96 hpi are intensified. The infiltrate is very dense, the epidermis is markedly thickened, the feeding lesion is poorly defined and the dermal tissue near the hypostome appears to be loosing its normal architecture. In conclusion, during D. andersoni feeding infiltration of inflammatory cells increases across time concurrent with significant changes in the epidermal and dermal compartments near the feeding tick. The importance of changes in the epidermal layer in the host response to ticks is not known, however, it is possible the host attempts to “slough off” the tick by greatly increasing epithelial cell replication.

Transcriptional profiling of the murine cutaneous response during initial and subsequent infestations with Ixodes scapularis nymphs

BackgroundIxodes scapularis ticks are hematophagous arthropods capable of transmitting many infectious agents to humans. The process of blood feeding is an extended and continuous interplay between tick and host responses. While this process has been studied extensively in vitro, no global understanding of the host response to ticks has emerged.MethodsTo address this issue, we used PCR-arrays to measure skin-specific expression of 233 discrete genes at 8 time points during primary and secondary infestations of mice with pathogen-free I. scapularis nymphs. Selected results were then validated at the mRNA and protein levels by additional real-time PCR and bioplex assay.ResultsPrimary infestation was characterized by the late induction of an innate immune response. Lectin pattern recognition receptors, cytokines, and chemokines were upregulated consistent with increased neutrophil and macrophage migration. Gene ontology and pathway analyses of downregulated genes suggested inhibition of gene transcription and Th17 immunity. During the secondary infestation, additional genes were modulated suggesting a broader involvement of immune cells including CD8 and CD4 positive T lymphocytes. The cytokine response showed a mixed Th1/Th2 profile with a potential for T regulatory cell activity. Key gene ontology clusters observed during the secondary infestation were cell migration and activation. Matrix metalloproteinases were upregulated, apoptosis-related genes were differentially modulated, and immunoreceptor signaling molecules were upregulated. In contrast, transcripts related to mitogenic, WNT, Hedgehog, and stress pathways were downregulated.ConclusionsOur results support a model of tick feeding where lectin pattern recognition receptors orchestrate an innate inflammatory response during primary infestation that primes a mixed Th1/Th2 response upon secondary exposure. Tick feeding inhibits gene transcription and Th17 immunity. Salivary molecules may also inhibit upregulation of mitogenic, WNT, Hedgehog, and stress pathways and enhance the activity of T regulatory cells, production of IL-10, and suppressors of cytokine signaling molecules (SOCS). This study provides the first comprehensive transcriptional analysis of the murine host response at the I. scapularis bite site and suggests both a potential model of the host cutaneous response and candidate genes for further description and investigation.

Immunohistochemical Characterization of Inflammatory Cells in the Skin of Cattle undergoing Repeated Infestations with Hypoderma lineatum (Diptera: Oestridae) Larvae

Cutaneous T- and B-cell responses were studied in three groups of cattle (n=4) after a primary (G1), secondary (G2) and tertiary (G3) experimental infestation with Hypoderma lineatum first instars (L1). Cattle were each infested with 25 L1 deposited onto the skin. Skin biopsies were taken at 0, 6, 12, 48, 96 and 144 h post infestation (hpi). The kinetics of infiltration of CD3(+), CD4(+) and CD8(+) T lymphocytes and B cells at the infestation site was evaluated immunohistochemically. The number and pattern of infiltration of CD3(+) T cells were similar in the different groups of animals, showing a progressive increase until 96 hpi. The number of CD4(+) T helper cells increased significantly at 96, 6 and 48 hpi in G1, G2 and G3, respectively. CD8(+) cytotoxic T-cell infiltration was similar in the different groups, except at 48 hpi when there was a significant difference between G1 and G3. The CD4:CD8 ratio showed predominance of CD4(+) cells throughout the response. The number of B cells increased with the number of previous infestations, with significant differences between G1 and G3 at 12 hpi. All of the cell types concentrated around the superficial and deep dermal vessels. During primary larval infestations there was a predominance of CD4(+) cells, whereas in cattle sensitized by previous infestations, B cells were most abundant in the infiltrate. These findings suggest that humoral immunity may play a significant role in bovine immunity to H. lineatum.

Imaging appearance of parasitic infestations of the breast: a report of two cases and review of the literature

Parasitic infestations of the breast are uncommon. They may occur as a part of generalized disease, or present as primary breast infestations, making diagnosis difficult. Clinically, they are difficult to differentiate from the more common breast pathologies. However, imaging plays an important role, and different modalities often help distinguish and diagnose these rare conditions.

Infections and infestations of the skin in children

Infections and infestations of the skin form a large proportion of skin diseases in children, especially in the tropics, but also in temperate areas. In many instances, superficial skin infections can be self-limiting as long as there is no impairment of the immune system, but some infections are chronic even when the immune responses are intact. In this review, we will concentrate on primary skin infections and infestations that are common in Europe, those potentially serious if not recognised and those in which recent advances have altered approach to management.

Characterisation of lesional infiltrates of dendritic cells and T cell subtypes during primary infestation of sheep with Psoroptes ovis, the sheep scab mite

Earlier studies of cattle and sheep have demonstrated that Psoroptes ovis infestations provoke an intense immunoinflammatory response dominated by eosinophils accompanied by a substantial infiltrate of lymphocytes. However, the kinetics of the lymphocyte response and the subtypes involved have not been characterised. We employed two groups of sheep to investigate the early (1-21 days) and later (21-63 days) infiltration of lymphocyte subpopulations and dendritic cells in primary infestations of sheep with P. ovis. Immunohistochemistry indicated that by 4 days after infestation numbers of CD4+ and CD45RA+ cells in lesional skin had increased significantly (P<0.03 and P<0.005, respectively) and that a significant increase in gammadelta T cells and dendritic cells (CD1b+) had occurred by 8 days (P<0.02 and P<0.01, respectively). Numbers of lymphocyte and dendritic cells declined from 49 to 63 days after infestation. Our observations suggest that mite-derived products exert a profound influence on the early recruitment of lymphocytes that may significantly influence the genesis of the adaptive immune response.

Temporal pattern of isotype-specific antibody responses in primary and challenge infestations of sheep with Psoroptes ovis--the sheep scab mite.

In sheep Psoroptes ovis provokes an allergic dermatitis with significant P. ovis antigen-specific IgE responses. The kinetics of the IgE response to primary and challenge infestations of P. ovis were reported earlier [Parasite Immunol. 22 (2000) 407]. The present study examines IgG, IgM and IgA responses to primary and challenge infestations of P. ovis and the profile of antigens/allergens reacting with IgG and IgE antibodies. Antigen-specific enzyme-linked immunosorbent assays (ELISAs) demonstrate that primary infestations elicited significant increases in levels of IgG and IgM but not IgA antibodies. IgG and IgM responses to primary and challenge infestations were not significantly different. Western blots of reduced P. ovis proteins indicate that IgG antibodies reacted with five major antigens following primary infestation and only three of these after challenge infestation. IgE antibodies bound to three major and five minor allergens after primary infestation and two additional minor allergens after challenge infestation. Immunodominant antigens >100 and <15 kDa and allergens >100 kDa were most consistent in stimulating substantial IgG and IgE antibody responses, respectively. These antigens/allergens may be exploited in immunodiagnosis and modulation of the host immune response.

Are Cutaneous Reactions to Fly Larvae Mediated by CD4+, TIA+ NK1.1 T Cells?

Background: Although there have been reports of fly larvae in wounds and as isolated primary infestations, there have been only rare reports documenting reactions to the larvae within the skin in humans and animals. There have been no reports documenting the histopathologic and immunohistochemical characteristics of the inflammatory infiltrate. Objective: We present a patient who developed local pruritus, erythema, and swelling approximately three weeks after infestation by a fly larva within the scalp. Histopathologically the biopsy site showed a mixed infiltrate containing lymphoid cells and numerous eosinophils. Immunohistochemical stains showed predominantly CD4+ T cells expressing an αβ T-cell receptor (TCR) of which approximately 30% coexpressed T-cell intracellular antigen (TIA) and CD56. In addition, there were approximately 5% of these CD4+ T cells which coexpressed CD30. Conclusions: Histopathologic and immunohistochemical findings are consistent with an effector cell population of cytotoxic CD4+ T cells that produce a T-helper 2 cytokine pattern. The phenotype of this subset of T cells is unique and among its characteristics is that antigens—usually nonprotein antigens—are presented to these CD4+, TIA+ natural killer (NK)1.1T cells by CD1d molecules.

Testosterone depresses innate and acquired resistance to ticks in natural rodent hosts: a force for aggregated distributions of parasites.

The effects of testosterone on acquired resistance to ticks, Ixodes ricinus, in their natural rodent hosts (voles, Clethrionomys glareolus, and wood-mice, Apodemus sylvaticus) were investigated by manipulating testosterone levels and exposing the hosts to repeated tick infestations. Testosterone reduced both innate and acquired resistance to tick feeding. During primary infestations, attachment rates were higher on rodents with high testosterone levels than on oil-implanted controls. Successive infestations on voles were accompanied by a decrease in tick feeding success and survival, but this decrease was significantly greater in ticks fed on control voles than in those fed on voles implanted with testosterone. When reduced feeding success had been induced, either by vaccination with tick salivary gland extract or by 4 successive infestations, implantation with testosterone partially reversed the acquired resistance. These effects of testosterone will generate heterogeneities within the rodent population with respect to tick distribution and microparasite transmission. The lowest innate and acquired resistance to tick feeding occurs in that fraction of the host population, i.e., sexually active males, most actively involved in the transmission of both Babesia microti and Borrelia burgdorferi s.l.

Cutaneous and systemic responses during primary and challenge infestations of sheep with the sheep scab mite, Psoroptes ovis.

Lesional area was estimated and lesional mast cells and eosinophils were counted during primary and challenge infestations of sheep with Psoroptes ovis. In addition, circulating basophils and eosinophils and serum P. ovis-specific immunoglobulin IgE antibody were quantified. Expansion of lesional area was significantly less and serum IgE titres significantly greater in challenge than primary infestations. Lesional mast cell hyperplasia and massive eosinophil infiltration accompanied by raised titres of P. ovis antigen-specific IgE antibody were compatible with an IgE-mediated Type-1 allergic reaction, while detection of lesional basophils was suggestive of cutaneous basophil hypersensitivity. The temporal pattern of lesional mastocytosis and eosinophil infiltration and the role of these cells and serum IgE in the immune response is discussed.

Sequential histopathology at the Rhipicephalus sanguineus tick feeding site on dogs and guinea pigs.

The tick Rhipicephalus sanguineus is a very common parasite of dogs worldwide. Dogs seem unable to acquire resistance against this tick species, whereas guinea pigs demonstrate a very strong resistance following primary infestation. We studied the inflammatory reaction at the R. sanguineus tick feeding site on dogs and guinea pigs during primary and tertiary infestations at different time intervals after attachment. Biopsies were collected after 4, 24, 48 and 96 hours. Changes that were found in all experimental groups included a cone of cement around the mouthparts of the tick, epidermal hyperplasia, edema and inflammatory cell infiltration in the dermis directly underneath the tick attachment site. Dogs reacted to ticks mainly with neutrophils, particularly after repeated exposure. Mast cells and mononuclear leukocytes were also present. Guinea pigs reacted to R. sanguineus mainly with mononuclear cells, eosinophils and basophils. These cells were particularly numerous after repeated exposure to R. sanguineus. Our results suggest that basophils and eosinophils are involved in resistance of guinea pigs to R. sanguineus and that neutrophils in dogs have little effect against this tick species.

Secondarily infected wounds and dermatoses: a diagnosis and treatment guide

Secondary bacterial skin infections are common complications of primary dermatoses, primary nonbacterial skin infections, traumatic lesions, ulcers, cutaneous infestations, and other miscellaneous skin diseases. Most diagnoses are based on information obtained by patient history and physical examination. Secondary bacterial skin infections may be polymicrobial, commonly include the pathogens Staphylococcus aureus and Streptococcus pyogenes , and require proper antibiotic treatment. The use of topical antibiotics avoids the risk of systemic allergic reactions or generalized side effects, and provides a high antibiotic concentration at the site of infection. Therefore, topical antibiotics should be considered as potential primary therapy in the emergency department. When systemic therapy is indicated, most commonly used agents for secondary skin infections are the penicillinase-resistant semi-synthetic penicillins; the first-generation cephalosporins, the macrolides; and combination antibacterials, such as amoxicillin/clavulanate potassium and trimethoprim/sulfamethoxazole.

Age-dependent immune response of chickens to feeding by Argas persicus larvae

Chickens of the dwarf Velsum breed acquired immunity to Argas persicus larvae during repeated infestations with 100 larval ticks in 2-week intervals, when primarily infested at the age of 10 weeks. This immunity was manifested by 74.6% and 75.9% rejection of larvae during secondary and tertiary infestation ( P<0.01), respectively, in relation to controls. The mean weight reductions observed were 16.5% and 12.2% in secondary and tertiary infestations, respectively ( P < 0.05). Weak immunity also occured after secondary and tertiary infestations in chickens infested first at the age of 6 and 8 weeks, but not in chickens aged 2 or 4 weeks at first infestation. No changes were observed in mean feeding periods of larvae engorged on chickens of all age groups ( P > 0.05). A significant increase in the leucocyte counts in peripheral blood ( P < 0.01 or P < 0.05), mostly of lymphocytes and heterophil granulocytes, followed each infestation in chickens of all age groups. Specific anti-tick circulating antibodies were detected by ELISA in the sera of 10-week-old chickens after primary infestations, in the 4–8-week chicken groups following secondary infestations when aged 6–10 weeks, and in the 2-week chicken group only after tertiary infestations, when the chickens reached the age of 6 weeks. A 53 kDa protein was recognized in the whole-body extract of larval ticks by immune serum during immunoblotting. This was probably the antigenic protein responsible for eliciting the circulating antibodies. The acquired immunity to ticks seen in chickens aged 6 weeks or more may be connected with maturation of the bursa of Fabricius and the development of complete immunocompetence, which is believed to occur in chickens at the age of 4–5 weeks.

Sarcoptes scabiei: The Circulating Antibody Response and Induced Immunity to Scabies

Scabies is an important parasitic disease that continues to persist throughout the world despite the availability of acaricides to control it. The immune response mechanism to scabies and the possible development of a vaccine for control of scabies was investigated. This study demonstrated that hosts infested with scabies develop immunity (resistance) to reinfestation. All hosts developed scabies-specific elevated circulating antibody titers during scabies infestations that followed the classical pattern for primary and secondary infestations. Parallel elevated levels of complement C3 were also observed. The hosts that exhibited acquired immunity after their first infestations had antibody and complement levels during challenge infestations lower than those of the hosts that showed no immunity when reinfested. Induction of immunity coupled with generally elevated antibody levels for both immune and nonimmune hosts suggested that resistance to reinfestation was associated with a cell-mediated response. These data also suggested that vaccination with specific scabies tissue containing the relevant antigens or recombinant relevant antigens could enhance the cell-mediated response to protect the hosts against natural infestations.

Analysis of the results obtained using a technic of experimental primary infestation with Fasciolahepatica in the rat

In this work, we analyzed the results obtained using a technic of infestation with Fasciola hepatica in the rat. The infestations were carried out with 30 metacercariae in a gelatin capsule. The humoral immune response, measured by ELISA, and the liver necroses, spleen size, number and length of the flukes recovered at necropsy were followed during the course of four experimental primary infestations. The results showed that the magnitude of the parasitic burden did not correlate with the humoral immune response of the rat. The study of the liver necroses, spleen size, fluke length and antibody titres showed that the use of 30 metacercariae in a capsule as a technic of infestation in the rat ensured the homogeneity of the parasite development and the humoral immune response of the host.

Aspects of the humoral and cell-mediated immune responses of sheep to the ked Melophagus ovinus (Diptera: Hippoboscidae).

Infestations by the sheep ked, Melophagus ovinus, stimulated the production of antibody toward sheep-ked proteins. Both primary and secondary antibody responses closely followed the rise and fall of 2 consecutive ked infestations on either innately resistant or susceptible sheep. Maximum titers coincided with peak ked populations and were attained 5.5 and 4 months after primary and secondary infestations, respectively. Acquired resistance was demonstrated for innately resistant and susceptible sheep, since both groups had significantly lower secondary infestations even though their antibody responses were similar to those observed for primary infestations. Lambs passively sensitized with immunoglobulin (IgG) developed resistance at the same rate as control lambs, and their peak ked populations and ked mortality were similar to those observed in controls. The proliferative response of peripheral blood lymphocytes to phytohemagglutinin (PHA) was significantly depressed at 5, 7, 19, and 21 wk postinfestation; however, a significant response to ked antigen was observed at 5 and 21 wk postinfestation. It is postulated that acquired resistance to keds is a chronic inflammatory response combined with specific immune effector elements.

Dermacentor variabilis: Acquired resistance to ticks in BALB/c mice

To assess the ability of Dermacentor variabilis larvae to feed on mice during repeated infestations, known numbers of larvae were confined to the skin of BALB/c mice within plastic capsules, and different skin sites were used in four successive infestations. In secondary infestations larval feeding appeared to be enhanced, but in subsequent infestations the mice expressed acquired tick resistance, manifested by reduction in numbers of engorged larvae and in weights of fed larvae. Resistance, once established, was still demonstrable four weeks after the previous infestation. Histological examination of skin biopsies from BALB/c mice undergoing repeated infestations revealed slight reactions to primary infestations and increasingly severe responses in subsequent infestations. The latter reactions included prominent participation of mast cells and eosinophils, many of which were degranulated close to tick bite sites. It is suggested that these cells might play a role in the expression of murine tick resistance.