Histopathology Of Infection Research Articles

Histopathology of infection and colonisation of Elsinoë ampelina on grapevine leaves

Elsinoe ampelina, the causal agent of grapevine anthracnose, infects all aboveground succulent parts of the plant, causing serious yield losses. There are no histopathological reports on this pathogen interaction with grapevine tissues. This study aimed at understanding the infection and colonisation processes of E. ampelina on Vitis labrusca cv. Niagara Rosada leaves by light, transmission and scanning microscopy. From one to five germ tubes per conidia were formed during conidia germination, predominantly one or two. Cuticle degradation was observed on plant surface underneath germ tubes and appressorium-like structures were rare. Monilioid and branched hyphae were observed 48 h post inoculation. Direct penetration occurred only on the adaxial leaf surface due to high trichome density on the abaxial leaf surface and conidia trapped on trichomes were frequently observed. The colonisation process was similar in the leaf blade, veins and petiole with the formation of inter- and intracellular hyphae. Phenolic compounds accumulated in infected areas; however, they did not prevent the colonisation progress. Tissues of foliar blade were totally changed by cell collapse and conidiogenous cells were observed on the surface of necrotic lesions. Ascus-like structures were observed within deeply unstructured tissues of leaf veins and necrotic areas of the petiole.

Histopathological comparisons of Staphylococcus aureus and Pseudomonas aeruginosa experimental infected porcine burn wounds.

Chronic skin wounds are a significant human health concern and are often complicated by infection with Pseudomonas aeruginosa and Staphylococcus aureus, particularly methicillin resistant S. aureus (MRSA). Translating the knowledge gained from extensive study of virulence mechanisms and pathogenesis of these bacterial species to new treatment modalities has been lacking in part due to a paucity of animal models able to recapitulate human disease. Our groups recently described a novel porcine chronic burn wound model for the study of bacterial infection; however, the histopathology of infection has yet to be described. The objective of this study is to define the histopathology of this model using important human chronic wound bacterial isolates. Porcine full-thickness burn wounds topically inoculated with P. aeruginosa strain PAO1, MRSA S. aureus strain USA300 or both bacteria were used to define and quantify histopathologic lesions. The development of a systemic, well-defined rubric for analysis allowed for evaluation of differences between infection groups. These differences, which included epithelial migration and proliferation, stromal necrosis, fluid accumulation and intensity and character of the innate and adaptive inflammatory cell responses, were identified temporally between infection groups. Mono-species infected wounds developed a hyper-proliferative wound edge. Coinfected wounds at day 35 had the largest wound sizes, increased amounts of neutrophilic inflammation, immaturity of the wound bed, and retention of necrotic tissue. Infection, regardless of species, inhibited wound contracture at all time points evaluated. Most importantly, this model recapitulated key features of chronic human wounds. Thus, this model will allow researchers to study novel treatment modalities in a biologically relevant animal model while monitoring both host and bacterial responses.

Molecular Characterization and Biochemical and Histopathological Aspects of the Parasitism of Haemoproteus spp. in Southern Caracaras (Caracara plancus).

Haemoproteid species have a wide global distribution, and they have been described in falcon species in several parts of the world. However, few studies in South America have focused on these birds. Haemoproteus spp. infections have been reported as the causative agents of serious histopathological changes, which can lead to the death of the host. Thus, this study aimed to molecularly and phylogenetically characterize Haemoproteus spp. in Caracara plancus, to characterize aspects of parasitism through clinical analysis and biochemical parameters, and to describe the histopathology of infection. To examine these aspects, 5 southern caracaras were examined clinically, and blood samples were collected. Blood smears were subsequently utilized in parasitemia calculations, PCR amplification, and serum biochemical investigations. Histological sections of the liver, kidneys, spleen, and heart were examined to check for possible histopathological changes. The birds showed clinical signs such as pallor and prostration that are consistent with Haemoproteus spp. infection. Moreover, the examination of the blood smears revealed 0.07% parasitemia in young gametocytes only. The PCR and sequencing results confirmed that the parasites belonged to Haemoproteus spp. The activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes, albumin, total serum proteins, and enzymatic urea were first described in C. plancus and serve as reference for future studies of bird species parasitized by Haemoproteus spp. Histopathology results showed signs of injury that were consistent with haemosporidian infection in the tissues of the analyzed organs. The present study is preliminary, and additional studies of Haemoproteus spp. infections in other bird species are needed to better understand the relationship between parasites and hosts, because despite the low parasitemia recorded, biochemical and histopathological changes in various organs were observed.

Parasitological and immunological aspects of early Ascaris spp. infection in mice

Studies related to the immunobiological aspects of an Ascaris spp. infection are still scarce, especially those that aim to elucidate the early events of the immune response. In this study, we demonstrated a novel standardized method for early experimental Ascaris infection, providing additional information about the infectivity of eggs embryonated in vitro as well as the influence of host age on development of the infection. Finally, we characterised the immunopathology of early infection, focusing on the tissue and systemic cytokine profiles and the histopathology of infection in the lungs of BALB/c mice. Our results demonstrated that the highest egg infectivity occurred on the 100th and 200th days of in vitro embryonation and that 8week-old BALB/c mice were more susceptible to infection than 16week-old mice. Ascaris-infected mice showed an early, significant level of IL-5 production in the lungs 4days p.i., followed by an increase in the level of neutrophils in the inflammatory infiltrate at 8days p.i, which was correlated with the peak of larval migration in the tissue and a significant level of IL-6 production. The inflammatory infiltrate in the lungs was gradually replaced by mononuclear cells and eosinophils on the 10th and 12th days p.i., respectively, and an increase in TNF levels was observed. The downmodulation of systemic TCD4+ cell numbers might suggest that T cell hyporesponsiveness was induced by the Ascaris spp. larvae, contributing to safeguarding parasite survival during larval migration. Taken together, the novel aspects of Ascaris infection presented here enabled a better understanding of the immunopathological events during larval migration, providing insight for further studies focused on immunisation and immunoprophylatic assays.

Histopathology of Infection and Colonization of Susceptible and Resistant Port-Orford-Cedar by Phytophthora lateralis

ABSTRACT Port-Orford-cedar (POC) root disease, caused by Phytophthora lateralis, continues to kill POC in landscape plantings and natural forests in western North America. POC trees resistant to P. lateralis have been identified and propagated. Cytological observations of P. lateralis in susceptible and resistant roots and stems were made with light and transmission electron microscopy to identify resistance mechanisms. No differences in infection pathway and initial colonization were observed between susceptible and resistant roots, although there were differences in the rate and extent of development. Germ tubes formed appressoria, and penetration hyphae grew either between or directly through epidermal cell walls; inter- and intracellular hyphae colonized the root cortex. In susceptible roots, hyphae penetrated into the vascular system within 48 h of inoculation. In contrast, hyphae in roots of resistant seedlings grew more slowly in cortical cells and were not observed to penetrate to the vascular tissues. In resistant roots, infection was marked by general thickening of cortical cell walls, wall appositions around penetrating hyphae, collapse of cortical cells, and accumulation of osmophillic granules around hyphae. In susceptible stems, hyphae grew inter- and intracellularly in all cells of the secondary phloem except fiber cells, but were concentrated in sieve and parenchyma cells in the functional phloem. The pattern of penetration and colonization of hyphae was similar in the resistant stems, except that hyphae were found in the fiber cells of the xylem. In resistant stems, there were fewer hyphae in the functional phloem, and cytological changes such as damaged nuclei and disintegrated cytoplasm were evident. Structural changes in resistant stems included collapsed cells, wall thickening, secretory bodies, apposition of electron dense materials, and crystals in cell walls.

Mycoplasma pneumoniae respiratory infection.

1. Nevio Cimolai, MD* 1. 2. *Director, Program of Microbiology, Virology, and Infection Control, Children’s and Women’s Health Centre of British Columbia, Vancouver, BC, Canada. 1. Mycoplasma pneumoniae remains the most common treatable cause of community-acquired atypical pneumonia in children. 2. Common features of M pneumoniae pneumonia include bilateral pulmonary involvement, multifocal or diffuse disease, and reticular infiltrates, but the radiologic manifestations are considerably more diverse. 3. Extrarespiratory manifestations potentially can include several body systems (eg, varied exanthemata, meningoencephalitis, arthropathy). These are either shortly preceded by or coexist with an active respiratory infection. 4. Cold agglutinin serology is of limited diagnostic value for children. 5. Erythromycin and tetracycline remain effective antimycoplasmal antibiotics; beta-lactam agents are not of value. One would anticipate that almost 4 decades of research and clinical experience should leave very little room for ongoing investigation of Mycoplasma pneumoniae . Nevertheless, respiratory infection caused by this pathogen remains common, and advances in science continue as unique attributes of the bacterium and the associated clinical illness unfold. Microbiologic and subsequently other investigations possibly have been delayed in part by the nature of the bacterium. Mycoplasmas are the smallest bacteria, and M pneumoniae in particular is sufficiently fastidious in vitro that few laboratories have provided culture services. Whereas Escherichia coli from a urine sample or Streptococcus pneumoniae from a cerebrospinal fluid specimen may be cultivated luxuriously in 18 to 24 hours, the isolation of M pneumoniae from sputum may require 7 to 21 days. These small, cell wall-deficient bacteria are impossible to visualize in respiratory secretions by either Gram stain or other light microscopic methods. In contrast to the rigid structure of other bacteria, mycoplasmas are pleomorphic (Fig. 1⇓ ). Indeed, the name mycoplasma refers to the plasticity of bacterial forms that crudely resemble some fungal filaments. Mycoplasmas, however, are not even remotely related to or even minimally resemble mycobacteria (eg, Mycobacterium tuberculosis ) or mycologic (ie, fungal) pathogens with respect to most other attributes. The lack of cell wall …

Pathology of congenital immunodeficiencies.

The histopathologic investigation of children with congenital immunodeficiency, and its relation to functional parameters and clinical data have been a major contribution to the present knowledge on the histophysiologic aspects of normal immune system function. Based on thorough knowledge in histophysiologic and dynamic aspects of lymphoid organs, the histopathologic evaluation in cases of suspected immunodeficiency today forms an integral part of the assessment of the immune status. Apart from conventional histologic techniques, advanced technology such as immunohistochemistry and in situ hybridization is applied. This enables analysis of the basic cellular components in various lymphoid tissue compartments, and evaluation of the consequences of the deficiency by the assessment of microorganisms and neoplasia. This review focuses on the histopathologic contribution to immunodeficiency evaluation. Sections deal with (1) the description of alterations in the various lymphoid tissues (bone marrow, thymus, lymph node, spleen, and gastrointestinal tissue); (2) histopathology of infection and malignancy; (3) pathology of some types of congenital immunodeficiency; (4) histopathologic methods and reagents; and (5) an autopsy protocol for immunodeficiency.

Experimental infection with Chlamydia pneumoniae in nonhuman primates

To serially examine the immunopathogenesis and histopathology of infection with Chlamydia pneumoniae, we inoculated two cynomolgus monkeys in the conjunctival sac, nose, and nasopharynx with C. pneumoniae TWAR. After inoculation, C. pneumoniae was isolated from the inoculation sites and the rectums of both monkeys for a period of 5 weeks. After a second inoculation, C. pneumoniae was recovered from the inoculation sites and the rectums of both monkeys for 20 weeks. A third inoculation with C. pneumoniae caused very little productive infection at any site. Prior C. pneumoniae infection did not prevent subsequent C. trachomatis serovar E (Bour strain) infection. Clinical and histopathologic ocular responses to C. pneumoniae infection were mild compared with those to infection with C. trachomatis serovar E. Rectal infection, demonstrated by culture isolation and immunohistopathology, occurred without direct experimental inoculation. Both immunofluorescent staining of mucosal smears with monoclonal antibodies and tissue culture were able to detect C. pneumoniae infection. Experimental nonhuman primate infection with C. pneumoniae appears to be clinically and histopathologically mild and can occur at extrapulmonary sites.

Survival of Macracanthorhynchus Ingens in Swine and Histopathology of Infection in Swine and Raccoons

Animal husbandry aimed at preventing Macracanthorhynchus hirudinaceus infections in swine is not successful in preventing exposure to Macracanthorhynchus ingens, and it is probable that pigs occasionally acquire acanthocephalans of that species. In some pigs, M. ingens survived 2 weeks and grew several millimeters. In such cases, destruction of villi, erosion of epithelium, leukocytic infiltration, and altered cytological structure at attachment sites accompanied the infection. Penetration was limited to the submucosa, and the effects were not as severe as those occurring in the presence of M. hirudinaceus, which enters the muscularis.

The effect of defective-interfering Semliki Forest virus on the histopathology of infection with virulent Semliki Forest virus in mice.

The majority of mice inoculated with a mixture of a lethal dose of virulent Semliki Forest virus (SFV) strain ts+ and defective-interfering (DI) SFV remained completely health, with virus infectivity levels in brain tissue reduced by 99.9%. The results of previous studies had suggested that these effects were primarily the result of the intrinsic interfering capacity of DI virus rather than of host defense responses. Because SFV strain ts+ and an avirulent strain of SFV have clearly distinguishable histopathologic effects in brain tissue, the capability of DI virus to change the virulent into the avirulent form of the disease was examined. Modulation of strain ts+ virus infection by DI virus was accompanied by a complete absence of histopathologic changes despite significant levels of infectious virus and thus differed qualitatively from infection with avirulent SFV. These results provide further evidence that the interference is not mediated through stimulation of an immune cell infiltration.

The histopathology of infection by Lepeophtheirus pectoralis (Müller) (Copepoda: Caligidae)

The histology of the pectoral fin of the flounder, Platichthys flesus. (L.), is described and the presence of eosinophilic granule cells in the epidermis was noted. The histopathological effects of infection by L. pectoralis result from the attachment and feeding activity of the parasite. Although the damage inflicted by L. pectoralis is usually confined to the epidermis the lesions caused by sessile life cycle stages, adult females and chalimus larvae, often extend into the dermis. In the dermis the inflammatory response comprised fibroplasia and cellular infiltration which resulted in the formation of a dense fibrous granulation tissue.

The haematology and histopathology of Trypanosoma congolense infection in cattle. I. Introduction and histopathology.

The reasons for making this study, to determine the haematology and histopathology of an infection caused by one species of trypanosome in one species of animal in the absence of intercurrent disease and other complicating factors, have been detailed. A histopathological examination suggested the presence of a chronic low-grade toxaemia and an anaemic hypoxia.

Fine Structure of the Hydatid Cyst and Protoscolex of Echinococcus granulosus

The fine structure of various parts of the hydatid cysts and the enclosed protoscolex is described. The contents of the brood capsule are PAS-positive following extraction treatment with amylase. This material is made up of fine irregularly arranged filaments, and remains as a coating over the posterior aspect of the protoscolex after its removal from the brood capsule. It has completely disappeared after 42 days in vitro. The posterior aspect of the protoscolex is with knoblike projections which are probably undeveloped tegumental projections. After 42 days culture in vitro this area has fully developed tegumental projections. Multinucleation of tegumental cells is common in the protoscolices cultured for 42 days in vitro. The various organ systems are described and compared with similar structures reported for tapeworms and other invertebrates. Although the teguments of several species of adult tapeworms have been examined by electron microscopy, the fine structure of the intermediate stages in their life history has been neglected. Goldschmidt (1900) was apparently the first to describe the spines on the body surface of developing protoscolices of Echinococcus granulosus, and subsequently Coutelen (1927) described the surface distribution of these spines in more detail. These authors, though limited to light microscopy, stated that the spines were seen only under ideal conditions with an oil immersion objective. More recent workers have made similar observations on the cystic stage of several taeniid tapeworms (Crusz, 1948; Voge, 1962, 1963). Waitz (1961) in describing the ultrastructure of the cystic stage of Hydatigera taeniaeformis mentions the presence of microvilli on the body surface. Larsh et al. (1965) in a study on the histopathology of infections in mice with the cystic stage of Multiceps serialis include an electron micrograph of a portion of cyst wall (their figure 7). Although a discussion of the fine structure is outside the scope of their paper, it is significant that their illustration clearly shows surface projections, vesicles within the tegument, and dark structures which may be mitochondria. Siddiqui (1963) examined the tegument of cysticerci of Taenia saginata, T. hydatigena, and T. pisiformis and noted that all three species were covered with hair-like processes. In an account of the ultrastructure of the Received for publication 27 July 1966. cystic stage of M. serialis, Race et al. (1965), reported that the subcuticular canals connect the cuticle with the parenchyma. Marzullo et al. (1957) reported the presence of mucopolysaccharides in the cyst of E. granulosus. Kilejian et al. (1961) demonstrated that the brood capsule contents are PAS-positive after saliva treatment. The electron microscopic appearance of this material has not previously been demonstrated. The investigation reported in this paper is an extension of previous work on the fine structure of adult taeniid tapeworms (Morseth, 1965, 1966) and especially that of E. granulosus. MATERIALS AND METHODS

Experimental infection with Mycobacterium johnei: II. The histopathology of infection in experimental goats

Experimental infection with Mycobacterium johnei: II. The histopathology of infection in experimental goats