A systematic review and meta-analysis of the aetiological agents of non-malarial febrile illnesses in Africa

Background

The awareness of non-malarial febrile illnesses (NMFIs) has been on the rise over the last decades. Therefore, we undertook a systematic literature review and meta-analysis of causative agents of non-malarial fevers on the African continent.

Methodology

We searched for literature in African Journals Online, EMBASE, PubMed, Scopus, and Web of Science databases to identify aetiologic agents that had been reported and to determine summary estimates of the proportional morbidity rates (PMr) associated with these pathogens among fever patients.

Findings

A total of 133 studies comprising 391,835 patients from 25 of the 54 African countries were eligible. A wide array of aetiologic agents were described with considerable regional differences among the leading agents. Overall, bacterial pathogens tested from blood samples accounted for the largest proportion. The summary estimates from the meta-analysis were low for most of the agents. This may have resulted from a true low prevalence of the agents, the failure to test for many agents or the low sensitivity of the diagnostic methods applied. Our meta-regression analysis of study and population variables showed that diagnostic methods determined the PMr estimates of typhoidal Salmonella and Dengue virus. An increase in the PMr of Klebsiella spp. infections was observed over time. Furthermore, the status of patients as either inpatient or outpatient predicted the PMr of Haemophilus spp. infections.

Conclusion

The small number of epidemiological studies and the variety of NMFI agents on the African continent emphasizes the need for harmonized studies with larger sample sizes. In particular, diagnostic procedures for NMFIs should be standardized to facilitate comparability of study results and to improve future meta-analyses. Reliable NMFI burden estimates will inform regional public health strategies.

Previous systematic reviews have highlighted the research priorities of causative agents for non-malarial febrile illnesses by counting the number of publications attributed to an agent. However, proportional morbidity rates are calculated by dividing the number of cases with a specific disease (numerator) by the total number of diagnosed fever cases (denominator) and are better indicators of the relative importance of aetiological agents in a population. Therefore, we present the leading causes of non-malarial febrile illnesses in African patients in both healthcare and community settings. Preference is given to HIV-negative patients when data could be found. We also determined summary estimates of Brucella spp., Chikungunya virus, Dengue virus, Haemophilus spp., Klebsiella spp., Leptospira spp., non-typhoidal Salmonella spp., typhoidal Salmonella spp., Staphylococcus spp., and Streptococcus spp.

The wide array of aetiological agents causing febrile illnesses on the African continent does not only complicate malaria control programs but may also hamper response to epidemic and pandemic illnesses such as Ebola and COVID-19. The harmonisation of diagnostics and study designs will reduce between-study differences, which may result in better estimates of disease burden on the continent and in the different African regions. This information is important for Pan-African surveillance and control efforts.

Parasites as negative regulators of cancer

Several environmental factors (chemical, physical, and biological) can cause the initiation, promotion, and progression of cancer. Regarding the biological factors, several studies have found that infections caused by some bacteria, viruses and protozoan, and helminth parasites are related to carcinogenesis. However, in recent years a different approach has been implemented on the antitumor impact of parasitic diseases caused by some protozoan and helminths, mainly because such infections may affect several hallmarks of cancer, but the involved mechanisms still remain unknown. The beneficial effects reported for some parasitic diseases on tumorigenesis range from the induction of apoptosis, activation of the immune response, avoiding metastasis and angiogenesis, inhibition of proliferative signals, to the regulation of inflammatory responses that promote cancer. In this work, we reviewed the available information regarding how parasitic infections may modulate cancer progression. Despite the fact that specific mechanisms of action on tumors are not yet totally clear, we consider that detailed studies of the antitumor action of these organisms and their products could lead to the discovery and use of new molecules from these biological agents that may work as adjuvant therapy in the treatment of various types of cancer.

Reestablishing rigor in archaeological parasitology

Archaeological parasitology originated in the mid-twentieth century with interdisciplinary teams of specialists directed by archaeologists. The goals of such studies were detailed analyses of dietary, medicinal, and environmental factors that shaped the patterns of infection. By the 1970s, a cadre of unique coprolite analysts was trained to analyze macroscopic and microscopic remains for integrated reconstructions of the cultural determinants of parasitism. During these first phases of research, diagnostic rigor was maintained by direct training of specialists in parasitology and archaeology sub-disciplines including archaeobotany and archaeopalynology. Near the end of the twentieth century, however, "paleoparasitology" was defined as a separate field focusing on defining parasite distribution through time and space. Ironically, this focus resulted in an increase in misdiagnosis, especially prominent after 2000. Paleoparasitology does not explicitly include other specialized studies in it research design. Thus, dietary, environmental and medicinal inferences have been neglected or lost as samples were destroyed solely for the purpose of parasitological analysis. Without ancillary archaeological studies, paleoparasitology runs the risk of separation from archaeological context, thereby reducing its value to the archaeologists who recover samples for analysis.

Taenia Solium Sneezed out from Nose by an Asymptomatic Child

Taenia solium is an intestinal parasite and may be excreted in feces in infected patients but our case is unique, as an asymptomatic child sneezed out the proglottids of the parasite from his nose. After the full course of antihelminthic drug the patient excreted a whole worm in his stool.

Role of fine needle aspiration biopsy cytology in the diagnosis of infections

The role of fine needle aspiration biopsy (FNAB) cytology in diagnosing infections has expanded due to the increase in the number of immune compromised patients and the increasing role of FNAB in the developing world where infection is a major cause of illness. FNAB has become the first procedural test in cases where the clinical and imaging findings suggest an infectious lesion or where there is a differential diagnosis of infection or metastatic or primary tumor. This applies to FNAB of palpable or image directed or deep seated lesions accessed by EUS and EBUS. This article details a recommended approach and technique for FNAB of infectious lesions, and discusses the role of rapid on site evaluation and the application of ancillary testing including the rapidly expanding array of molecular tests based on FNAB material. The utility of recognizing suppurative and granulomatous infectious patterns in FNAB direct smears, and the specific cytomorphological features on routine Papanicolaou and Giemsa stains and on special stains of FNAB smears is described for a large number of bacterial, fungal, viral, parasitic, and protozoan infections. The role of cytopathologists is to now train cytopathologists in sufficient numbers to provide FNAB services, teach trainee cytopathologists and cytotechnologists, and to encourage our clinical colleagues to use FNAB in the diagnosis of infections and other lesions to the benefit of patients and the medical system. Diagn. Cytopathol. 2016;44:1024-1038. © 2016 Wiley Periodicals, Inc.

Different regulatory mechanisms in protozoan parasitic infections

The immune response to the protozoan pathogens, Leishmania spp., Trypanosoma spp. and Plasmodium spp., has been studied extensively with particular focus on regulation of the immune response by immunological mechanisms. More specifically, in diseases caused by parasites, immunosuppression frequently prevents immunopathology that can injure the host. However, this allows a small number of parasites to evade the immune response and remain in the host after a clinical cure. The consequences can be chronic infections, which establish a zoonotic or anthroponotic reservoir. This review will highlight some of the identified regulatory mechanisms of the immune system that govern immune responses to parasitic diseases, in particular leishmaniasis, trypanosomiasis and malaria, and discuss implications for the development of efficient vaccines against these diseases.

[Procedure and indications of stool examination in parasitology]

Intestinal parasites are a public health problem in the world especially in tropical and subtropical countries. Despite the improvement in living standards and healthy conditions, these parasitoses remain relatively frequent in Tunisia. Stool specimen examination keeps the fundamental test for screening and diagnosis. It is to directly search the parasite. Respect for the right procedure of collection of stool is an essential step for the reliability and proper interpretation of results of this examination.

Cutaneous manifestations of systemic tropical parasitic diseases

Tropical diseases continue to cause significant health problems in developing nations. An overview of illnesses with notable cutaneous findings caused by protozoans and helminthes is provided. The role of the health care provider in disease management is described.

Web-based virtual microscopy for parasitology: a novel tool for education and quality assurance

Background

The basis for correctly assessing the burden of parasitic infections and the effects of interventions relies on a somewhat shaky foundation as long as we do not know how reliable the reported laboratory findings are. Thus virtual microscopy, successfully introduced as a histopathology tool, has been adapted for medical parasitology.

Methodology/Principal Findings

Specimens containing parasites in tissues, stools, and blood have been digitized and made accessible as a “webmicroscope for parasitology” (WMP) on the Internet (http://www.webmicroscope.net/parasitology).These digitized specimens can be viewed (“navigated” both in the x-axis and the y-axis) at the desired magnification by an unrestricted number of individuals simultaneously. For virtual microscopy of specimens containing stool parasites, it was necessary to develop the technique further in order to enable navigation in the z plane (i.e., “focusing”). Specimens were therefore scanned and photographed in two or more focal planes. The resulting digitized specimens consist of stacks of laterally “stiched” individual images covering the entire area of the sample photographed at high magnification. The digitized image information (∼10 GB uncompressed data per specimen) is accessible at data transfer speeds from 2 to 10 Mb/s via a network of five image servers located in different parts of Europe. Image streaming and rapid data transfer to an ordinary personal computer makes web-based virtual microscopy similar to conventional microscopy.

Conclusion/Significance

The potential of this novel technique in the field of medical parasitology to share identical parasitological specimens means that we can provide a “gold standard”, which can overcome several problems encountered in quality control of diagnostic parasitology. Thus, the WMP may have an impact on the reliability of data, which constitute the basis for our understanding of the vast problem of neglected tropical diseases. The WMP can be used also in the absence of a fast Internet communication. An ordinary PC, or even a laptop, may function as a local image server, e.g., in health centers in tropical endemic areas.

Here, we describe a novel tool to observe parasites by virtual microscopy on the Internet. Microscopy-based identification of parasites is the basis for both diagnostics and epidemiological assessment of parasite burden globally. Yet, quality assessment of diagnostic parasitology laboratories is difficult, as delivering identical educational specimens has been impossible. In this study, a series of parasite specimens on ordinary glass slides were digitized using a recently developed microscope scanner technique. Up to 50,000 images captured at high magnification are digitally stitched together to form a representation of the entire glass slide. These “virtual slides” digitized at a thousand-fold magnification can hold more than 60 gigabytes of data. Handling such large amounts of data was made possible because of efficient compression techniques and a viewing system adopted from the geospatial imaging industry. Viewing the samples on the Internet very much resembles, for example, the use of Google Maps, and puts only modest requirements on the viewer's computer. In addition, we captured image stacks at different focal planes, and developed a web-based viewing system for three-dimensional navigation in the specimens. This novel technique is especially valuable for detailed visualization of large objects such as helminth eggs in stool specimens.

The health impact of polyparasitism in humans: are we under-estimating the burden of parasitic diseases?

Parasitic infections are widespread throughout the tropics and sub-tropics, and infection with multiple parasite species is the norm rather than the exception. Despite the ubiquity of polyparasitism, its public health significance has been inadequately studied. Here we review available studies investigating the nutritional and pathological consequences of multiple infections with Plasmodium and helminth infection and, in doing so, encourage a reassessment of the disease burden caused by polyparasitism. The available evidence is conspicuously sparse but is suggestive that multiple human parasite species may have an additive and/or multiplicative impact on nutrition and organ pathology. Existing studies suffer from a number of methodological limitations and adequately designed studies are clearly necessary. Current methods of estimating the potential global morbidity due to parasitic diseases underestimate the health impact of polyparasitism, and possible reasons for this are presented. As international strategies to control multiple parasite species are rolled-out, there is a number of options to investigate the complexity of polyparasitism, and it is hoped that that the parasitological research community will grasp the opportunity to understand better the health of polyparasitism in humans.

[The heart in cases of viral, bacterial and parasitic infections]

The heart can be the primary target for a viral, bacterial or parasitic infection (primary myocarditis/inflammatory cardiomyopathy). It can also participate in the "collateral damage" due to toxins, chemo- and cytokines, autoreactive antibodies or the native and acquired immune response through T- and B-cells, monocytes and macrophages (secondary myocarditis/inflammatory cardiomyopathy), when it is not the dominant organ of the disease. Infective agents show remarkable organ specificity: viral infections, toxic and autoreactive processes affect primarily the myocardium and the pericardium, whereas bacterial infections prefer endothelial surfaces and cause endocarditis and, less frequently, pericarditis. They are even discussed as part of the inflammatory process involved in coronary artery disease. Infective agents and their adequate diagnosis and treatment are discussed for these clinical entities according to current guidelines and clinical pathways.

The archaeology of apoptosis

Human death has been recognised as a significant personal and social event for many thousands of years, and classical archaeologists have revealed the changing complexity of rituals associated with it. The study of cell death, however, is a much more recent event, although many of the molecular pathways involved have now been identified, at least in mammalian systems. In studying the loss of cells, the use of the term 'death' is, perhaps, not altogether appropriate both since it carries the cultural resonance associated with bodily death, and because we do not study cell death itself, but rather the processes that lead up to it. Mammalian cell death processes are complex and involve a dynamic equilibrium between death promoting and death inhibiting factors, suggesting that some components of death pathways may have a paradoxical survival function. Since parasites must survive an often hostile environment, they may be a useful model to study whether component molecules of mammalian death pathways originally formed modules of parasite survival strategies, and whether survival and death pathways coevolved.

Description of microscopic lesions of vestibular folds of autopsied adults and their relationship with cause of death and underlying disease

The increase in invasive methods currently applied to diagnosis airway upper tract infection leads to a possible increase in vestibular folds (VF) lesions. Besides, VF importance in the prevention of the organism against infection pathogens had been stressed and few studies had addressed the microscopic lesions of the VF in autopsied patients because there is no routine VF examination in the postmortem exam.

Aim

The aim of this study is morphological microscopic analyses of the VF from autopsied patients and its correlation with basic disease and cause of death.

Study design

transversal cohort.

Material and Method

We studied 82 larynges collected during the autopsy exam and performed the Hematoxylin -eosin method for morphological analyses.

Results

From the 82 vestibular folds analyzed we observe that 42 (51%) showed an inflammatory reaction. In fifteen (18.3%) vestibular folds we found lymphoid follicular hyperplasia, in eleven (13.4%) diffuse inflammatory infiltrate and in sixteen (19.5%) acute inflammatory reactions. Circulatory diseases were the most frequently underlying diseases found, 31 (37.8%) and from these 20 (67.8%) presented associated vestibular folds inflammatory reaction. The infection diseases were the most frequently cause of death among the patients with inflammatory reaction of the VF.

Conclusion

Besides the anatomic function, VF seem to have a immunological function preventing lower airway infections. Our study demonstrated inflammatory PV reactions in patients with infections diseases as cause of death; this finding could be a consequence of the sepses that leads the patient to death or a different way used by the organism to prevent infection.

Anemia and childhood mortality: Latitudinal patterning along the coast of pre-Columbian Peru

Hrdlicka ([1914] Smithson. Inst. Misc. Collect. 61:1-69) reported that pre-Columbian skeletal material from the coastal lowland Andean region exhibited a high frequency of porotic hyperostosis, a pathological condition of bone that generally is thought to indicate childhood anemia. While subsequent studies tended to reinforce this conclusion, factors implicated in the condition have yet to be fully explored in the region as a whole. This study explores regional and intravalley variation as one step in establishing biocultural variables that increase the apparent risk of childhood anemia. The study sample includes 1,465 individuals: 512 from Peruvian collections housed at the Field Museum of Natural History, and 953 from systematically excavated contexts from Moquegua, Peru. Environmental stressors, such as parasites and disease, rather than specific dietary practices were found to be more likely associated with childhood anemia in these coastal Andean samples. The study supports cribra orbitalia as an earlier expression of porotic hyperostosis and suggests that porotic hyperostosis, as recorded here, cannot be easily dismissed as a result of cranial shape modification. No clear temporal patterns were observed. Finally, the study establishes that comparing data for children and adults can reveal the relative association between childhood anemia and mortality. Childhood mortality associated with anemia was elevated where the presence of tuberculosis or tuberculosis-like conditions was more common and the presence of water-borne pathogens was negligible. In contrast, those buried at lower altitudes, closer to the coast, and consuming mainly marine resources were less likely to die in childhood with anemia than in the other contexts studied.

[Histology in diagnosis of parasitic diseases]

Many pathogenic organisms cause inflammatory lesions and microscopic findings are a useful diagnostic tool for the aetiological diagnosis. However, the histological lesions are limited in respect to many biological agents that can damage the tissues. The histologic hallmark of parasitic diseases is mostly granulomatous inflammation. It is characterized by a focal infiltration of macrophages and epithelioid cells. Many giant cells, lymphocytes, plasma cells, fibroblasts and granulocytes can be found. Agents inducing granulomas include helminths and parasites that replicate intracellularly. Some special stains are utilized in histopathology, for example Giemsa's stain is useful to identify Leishmania. Using specific antibodies, immunohistochemical methods provide an aetiological diagnosis. Sometimes, tissue damage can be immuno-mediated depending on deposit of circulating immunocomplexes or T-lymphocytes involvement rather than by direct parasitic injury. Generally, the lesions which can be observed are respectively vasculitis and inflammatory reactions predominantly composed of mononuclear cells, as observed in many viral or bacterial diseases. In these cases, aetiological diagnosis is improved by in situ-PCR. For microscopic identification of parasites in tissues it is also important to be familiar with the kind of parasites most likely to be found in the examined tissue and in that particular host. Localization of parasites can induce hyperplastic-neoplastic lesions. Many parasites have been associated with the occurrence of specific types of neoplasms, but the mechanisms involved are still not well defined. Chronic inflammation and/or immune suppression seem to induce neoplastic proliferation.

[Cytopathologist's role in detecting and identifying pathogens]

This review highlights the contribution of the cytopathologist in the diagnosis of infectious diseases, with emphasis on the detection and identification of microorganisms in various cytologic specimens. Morphological analysis of the main bacteria, parasites and mycoses observed in cytologic specimens, as well as the cytopathogenic effects of the viruses are discussed. The differential diagnosis (contaminants and exogenous or endogenous foreign bodies) is discussed. Finally, the main pathogens noted in each specimen are briefly reviewed.

Pathological differentiation of suspected cases of pentastomiasis in China

We report nine cases of suspected pentastomiasis from China, and propose that diagnosis of this rare parasitic disease should be made aetio-pathologically, subaetio-pathologically, and presumptively. In none of our cases' lesions we could find either a whole or part of an embedded nymph; hence, no aetio-pathologic diagnosis of pentastomid infection was established. In three cases, subaetio-pathologic diagnoses of pentastomiasis were made upon the discovery of a peculiar set of relics from lesions, namely two pairs of circumoral hooks of pentastomid from lesions. In one of these three cases, an extra scissors-like image indicating a longitudinal section of a hook of the embedded pentastomid nymph, probably Linguatula serrata, was found. In the other six cases, none of the relics of the aetiological agents were found, and our diagnoses were made presumptively by a series of relatively specific pathologic features, i.e. pearly lesions over the peritoneal surface of the abdominal cavity under the serosa of the intestinal wall or under the capsules of liver and spleen. They tend to be uniquely protuberant, sometimes linked by a short thin stalk to the surface. The hyalinization and calcification of these centrally caseated granulomatous nodules tend to be concentric and targetoid in appearance. Tuberculosis, the most easily confused condition, was easily ruled out pathohistologically. We believe that there is a need for presumptive pathologic diagnosis of human pentastomid infection not only in China, but worldwide.

[Diagnostic pitfalls in infectious disease pathology]

Numerous images observed in histopathology and cytopathology can mimic pathogens such as mycotic agents, parasites (protozoa or helminthes), bacteria or virus. An error of diagnosis may provoke the administration of a non efficient treatment which can also be toxic. The present review describes these false pathogens which can correspond to exogenous or endogenous agents. Basic morphological analysis of mycotic agents, parasites, bacteria and cytopathogenic viral effects are successively presented. Then, the main diagnostic pitfalls which can be observed during these infections are exposed. Finally, diagnostic problems occurring in case of contamination are rapidly cited.

Application of stains in clinical microbiology

Stains have been used for diagnosing infectious diseases since the late 1800s. The Gram stain remains the most commonly used stain because it detects and differentiates a wide range of pathogens. The next most commonly used diagnostic technique is acid-fast staining that is used primarily to detect Mycobacterium tuberculosis and other severe infections. Many infectious agents grow slowly on culture media or may not grow at all; stains may be the only method to detect these organisms in clinical specimens. In the hands of experienced clinical microscopists, stains provide rapid and cost-effective information for preliminary diagnosis of infectious diseases. A review of the most common staining methods used in the clinical microbiology laboratory is presented here.

Pyogenic abscesses and parasitic diseases

Parasitic diseases which during their course in the host switch the immune system from a T helper 1 to a T helper 2 response may be detrimental to the host, contributing to granuloma formation, eosinophilia, hyper-IgE, and increased susceptibility to bacterial and fungal infections. Patients and animals with acute schistosomiasis and hyper-IgE in their serum develop pyogenic liver abscess in the presence of bacteremia caused by Staphylococcus aureus. The Salmonella-S. mansoni association has also been well documented. The association of tropical pyomyositis (pyogenic muscle abscess) and pyogenic liver abscess with Toxocara infection has recently been described in the same context. In tropical countries that may be an interesting explanation for the great morbidity of bacterial diseases. If the association of parasitic infections and pyogenic abscesses and/or fungal diseases are confirmed, there will be a strong case in favor of universal treatment for parasitic diseases to prevent or decrease the morbidity of superinfection with bacteria and fungi.

An ultrastructural study of sporidium formation during infection of a rhabditid nematode by large gun cells of Haptoglossa heteromorpha

Recently fired gun cells of Haptoglossa heteromorpha, an aplanosporic nematode parasite, were examined ultrastructurally. The everted tubes of the fired cells had penetrated the cuticle of a nematode, and infective sporidia were developing inside the host body. The nematode cuticle was penetrated by the narrow, walled part of the tube below the needle chamber. The lower unwalled part of the tube tail formed the sporidium. The developing sporidium had a multilayered fibrous outer coating and the plasma membrane was separated from the wall in places. Sporidia contained biphasic membrane-bound vesicles that had been generated by the Golgi dictyosome during gun cell development. Immediately following gun cell firing, the nuclear envelope of the sporidium nucleus was not apparent, and the sporidium nucleus contained clusters of electron-dense particles concentrated in the nucleolar region. We compare the structures and organelles found in the mature gun cell with those in the fired cell and attempt to identify the membranous layers around the sporidium.

Gastrointestinal parasites presentations and histological diagnosis from endoscopic biopsies and surgical specimens

OBJECTIVE

To diagnose parasitic ova or worms during endoscopy, surgery or by histology from endoscopic or surgical specimen in our patients.

METHODS

The diagnosis of parasitic disease in our patients was made by histological examinations from biopsies obtained either during an upper gastrointestinal or lower gastrointestinal endoscopy or from surgical specimens.

RESULTS

Parasites were seen in endoscopic biopsies from upper gastrointestinal tract in 21 patients. Schistosoma ova was seen in biopsies from stomach or duodenum (12 patients). Small intestine biopsies showed Giardiasis (8 patients) and strongyloides (1 patient). Colonic biopsies showed schistosoma ova by paraffin section or by squash technique in 216 patients. Surgical specimens from 12 patients, who presented with acute abdomen and had surgery, due to appendicitis in 8 patients, in whom specimens showed (Schistosoma in 5 patients, amoebiasis in 2 patients and Trichuria in 1 patient). Four other patients presented with acute abdomen, where ischemic bowel necrosis or mesenteric vein thrombosis was found during surgery, specimens showed schistosoma ova.

CONCLUSION

The diagnosis of gastrointestinal parasites is not only made by stool but the diagnosis can be made by histology from endoscopic biopsies or surgical specimens.

Eicosanoids in parasites and parasitic infections

Eicosanoids are lipid mediators with multiple functions in vertebrate tissues and invertebrate organisms. In this review the roles of eicosanoids--mostly prostaglandins (PGs), thromboxanes and leukotrienes--in parasite physiology and host-parasite interactions are discussed. PGs are present in the saliva of blood-sucking arthropods facilitating feeding by increasing local blood flow and prolonged attachment of ticks by immune suppression. Release of various eicosanoids has also been demonstrated for a number of protozoan and metazoan endoparasites. These substances appear to play a role in penetration, immune suppression, inflammation or modulation of haemostasis, enabling parasite invasion and establishment. Moreover, endogenous eicosanoids serve various functions in parasite metabolism and physiology. In many parasitic infections eicosanoids are involved in host pathology, e.g. granuloma formation, coagulopathy, secretory diarrhoea, or fever. Immune suppression by induction of PG release, in particular PGE2, by host defence cells appears to be a common feature of many parasitic infections and is though to be important for parasite establishment. Contradictory results have been obtained for gastrointestinal nematode infections, which probably reflect the considerable differences between the various models employed. Although most of the available studies indicate an important role for eicosanoids in parasites and parasitic infections, our current knowledge is still fragmentary and more data are urgently needed.

[Overview of tropical endoparasitic diseases with cutaneous manifestations]

Among the diverse endoparasitic disorders some are primary cutaneous disorders and others exhibit signs on the skin in association with predominant internal manifestations. A variety of protozoans and helminths are responsible for these disorders.

Occurrence of prostaglandins and other eicosanoids in parasites and their role in host-parasite interaction

Prostaglandins have been already pretty well recognized as metabolic regulators in vertebebrata tissues mainly in mammals. I.ess reports concerned the occurrence of prostaglandins in invertebrates. In the present review we summarise literature data about the presence of prostaglandins and other eicosanoids in various groups of parasites and their possible role in host-parasite interaction. Prostaglandins have also been found in very primitive organisms as bacteria, varions plants and protozoa. We summarise that prostaglandins seem to be a very ancient group, going back to the roots of evolution. They are as universal in cell physiology as DNA in genetics. In host-parasiter eicosanoids also parasitic origin, play an important role as a modulators of hosts immune responsiveness.

Transforming growth factor beta in infectious disease: always there for the host and the pathogen

At the portals of pathogen entry, there are pools of the latent form of a potent cytokine, transforming growth factor beta (TGF-beta). Many infections activate these pools and stimulate further TGF-beta expression. As well as potent immunomodulation, activated TGF-beta might have important effects on pathogen entry, replication, persistence, latency and oncogenesis.

[Human parasitoses in Burkina Faso. Histopathologic approach]

The aim of this first study was to assess parasitic diseases encountered in histological practice in Burkina Faso. An examination of 3410 pathological specimens showed 138 cases of parasitic diseases which represented 4% of the results observed for 5 years in the laboratory of YALGADO OUEDRAOGO National Hospital. The parasitic diseases diagnosed were in decreasing order Schistosomiasis 53.6%, Cysticercosis 13.1%, Mycetoma 12.3%, Cutaneous Leishmaniasis 8%, Amebiasis 6.6%, Filariasis 4.3%, and Histoplasmosis 2.1%. We recommend better data collection for integration of these diseases into the health policy of Burkina.

Diagnosis of infectious diseases: a cytopathologist's perspective

This review explores the role of the cytopathology laboratory in the detection and presumptive identification of microorganisms. Sample procurement by exfoliation, abrasion, and aspiration techniques, as well as a variety of cytopreparatory and staining methods, is reviewed. Emphasis is placed on the utility of fine-needle aspiration as a rapid, safe, and cost-effective diagnositic procedure. The role of rapid interpretation and specimen triage is also discussed. Cytomorphologic features and staining characteristics are presented for a spectrum of microorganisms potentially encountered in the cytopathology laboratory. Pitfalls in diagnosis and the usefulness of special stains and ancillary techniques are also evaluated. The importance of communication, collaboration, and clinical correlation is stressed.

Haemobaphes disphaerocephalus, an accidental parasite of seawater pen-reared Atlantic salmon

Gill infections by the parasitic copepod Haemobaphes disphaerocephalus (family Pennellidae) were observed on a few Atlantic salmon reared at 2 seawater netpen sites in British Columbia. This is the first report of this parasite affecting salmonids. The terminal holdfast penetrated into a branchial artery and was associated with anemia.

Controlled efficacy study of the bioequivalence of Strongid C and generic pyrantel tartrate in horses

The bioequivalence of Strongid C and generic pyrantel tartrate was determined in a controlled study using 30 horses with naturally acquired endoparasitic infections. Three horses were randomly allocated to each of ten replicates based on quantitative nematode and ascarid egg counts and fecal larvae culture results. Horses within each replicate were randomly assigned to one of three treatment groups. Horses in Treatment Group 1 received only oats; horses in Treatment Group 2 received generic pyrantel tartrate pellets (2.65 mg pyrantel tartrate kg-1) mixed with oats; horses in Treatment Group 3 were fed Strongid C pellets (2.65 mg pyrantel tartrate kg-1) mixed with oats. Horses were treated daily for a 30 day continuous treatment period. At the termination of the study the horses were necropsied and endoparasites recovered, identified, and enumerated. In all instances, no significant difference (P > 0.05) in mean numbers of parasites recovered existed between horses treated with generic pyrantel tartrate and Strongid C. Numbers of gastrointestinal parasites recovered from horses treated with generic pyrantel tartrate or Strongid C were shown to be significantly different (P < 0.05) from numbers of gastrointestinal parasites recovered from non-treated controls for the large strongyles (Strongylus vulgaris, S. edentatus, and Triodontophorus spp.), small strongyles (Cyathostomum spp., Cylicocyclus spp., and Cylicostephanus spp.) and fourth-stage Parascaris equorum. Numbers of adult P. equorum recovered from horses treated with Strongid C were also significantly different (P < 0.05) from those from non-treated controls. Numbers of adult P. equorum recovered from horses treated with generic pyrantel tartrate were not significantly different (P = 0.0761) from those from non-treated controls. The determination of bioequivalence was based upon the 95% confidence interval of the difference between the mean number of parasites recovered from horses treated with generic pyrantel tartrate and the mean number of parasites recovered from horses treated with Strongid C. For all instances in which the numbers of parasites recovered from horses treated with either Strongid C or generic pyrantel tartrate were significantly different from the numbers of parasites recovered from non-treated controls, bioequivalence was demonstrated.

Parasitic infections of the central nervous system in children. Part III: Space-occupying lesions

In the last part of this three-part review of parasitic infections of the central nervous system in children, we consider parasites which due to their size, distribution, or the nature of the host response, tend to cause focal lesions in the brain and spinal cord and therefore present as space-occupying lesions which occasionally mimic malignant tumors. As in Parts I and II, infections are grouped according to their predominant geographic area. Such infections include cysticercosis, one of the more common and important infections of the central nervous system.

Non-neoplastic lesions in beluga whales (Delphinapterus leucas) and other marine mammals from the St Lawrence Estuary

In a 3-year (1988-1990) pathological study, 24 carcasses of beluga whales from the St Lawrence Estuary, Québec, Canada, showed numerous severe lesions, many of which had never been reported in cetaceans. The most common lesions were found in the digestive tract (21 animals) and consisted mainly of periodontitis and of erosions and ulcers in the oesophagus and the first two gastric compartments. Pneumonia, usually of parasitic origin, was also a common finding (12 animals). The adrenal glands often contained nodules (five animals) or cysts (seven animals), and mastitis was observed in five females. Overall, the incidence of degenerative, infectious, hyperplastic or necrotic lesions, in addition to numerous neoplasms described in another paper, was considerably higher than that found in marine mammals elsewhere or in other species of marine mammal from the same waters.

Parasitic infections of the central nervous system in children. Part II: Disseminated infections

In the second segment of this three-part review of parasitic infections of the central nervous system in children, we consider parasitic infections which typically involve various tissues and organs in addition to the brain and spinal cord. Parasites capable of dissemination in immunocompetent hosts are discussed first, and, as in Part I, organisms are grouped according to their predominant geographic location. This is followed by a discussion of the unique aspects of toxoplasmosis, strongyloidiasis and infection with microsporidia in immunocompromised patients, with an emphasis on the central nervous system.

Extracellular matrix degradation in parasitic diseases

1. Fibrosis is an important manifestation of several parasitic diseases, but is not irreversible. A marked degree of extracellular matrix degradation can occur after cure of parasitism. Patients with the hepatosplenic form of schistosomiasis undergo considerable resorption of portal fibrosis months or years after curative treatment as demonstrated by ultrasonography and pathological examination. 2. Studies of the post-treatment degradation of extracellular matrix in schistosomal periovular granulomas have demonstrated two forms of collagen degradation: in hepatic granulomas formed during early infection a rapid process occurs, with the extracellular breakdown of fibers and internalization of collagen fragments, whereas during late infection, degradation is slow and is accompanied by focal electrondense and/or lytic changes. 3. Extensive extracellular matrix degradation and resorption occurring after curative treatment was recently described in the liver of a man with advanced visceral leishmaniasis and in the heart of mice with chronic Chagas' disease.

Disease-husbandry associations in farmed crocodiles in Queensland and the Northern Territory

To investigate husbandry-disease associations in farmed crocodiles 7 farms in Queensland and the Northern Territory were visited and details of past and present farm design and husbandry practices were recorded. In addition pathological examination of 300 (mostly young) crocodiles was carried out (85 necropsied, one biopsied and 214 examined retrospectively). Mortality rate and occurrence of disease, especially opportunistic infections with bacteria and fungi, were highest during winter months and in farms located at greater latitudes. A difference in the presence and prevalence of disease between the initial establishment phase of Northern Territory crocodile farms (1984-87) and currently (1988-91) was apparent; parasitic infections are now relatively infrequent and bacterial septicaemias and mycoses less common as a result of some provision of artificial heating for juveniles. Gross and microscopic changes observed in visceral and periarticular gout, bacterial hepatitis/septicaemia, deep and superficial mycosis, pentastomiasis and other parasitic infections are described.

[Status of parasitic infection diagnosed by surgical biopsy in Kwangju and Chollanam-do]

In order to know the species and frequency of human parasitic infection diagnosed by biopsy, 149 cases (0.18%) of parasitic infection were reviewed, which were selected from 80,947 biopsied materials submitted for routine histopathological examination during a period of 10 years from 1980 to 1989 at Department of Pathology, Chonnam National University Hospital. They consisted of 112 cases of cysticercosis, 17 paragonimiasis, 7 clonorchiasis, 4 amebiasis, 1 sparganosis, 1 enterobiasis, 1 anisakiasis, and 1 fascioliasis respectively. Based on morphological preservation of cysticercus, they could be divided into mild (20.2%), moderate (40.4%), and severe (39.4%) degeneration. Except 2 cases biopsied at the lungs, 15 cases of ectopic paragonimiasis were located at abdominal cavity (8 cases) and central nervous system (7 cases). One case of intrahepatic fascioliasis was observed. This is the 13th human fascioliasis reported in Korea. From the above results, the frequency of parasitic infections found in biopsied specimens was on the decrease as the year passed by, but biopsy is very useful diagnostic method on tissue parasites such as cysticercosis and ectopic paragonimiasis.

[Significance of bone marrow cytology in the diagnosis of leukosis in dogs]

In the differential diagnosis of neoplastic diseases of blood cells or their precursors, cytological examination of bone marrow is a valuable diagnostic tool. Depending on the expected cell type, an aspiration followed by clinical-cytological examination, or a biopsy followed by histopathological examination is indicated. In all unclear cases of cytopenia, if blood parasites or a lymphatic leukemia without tumors are suspected or in myeloproliferative diseases, bone marrow cytology can provide the diagnosis. If the aspiration of bone marrow is not possible in spite of correct technique (punctiosicca), myelofibrosis must be suspected. The diagnosis is confirmed by bone marrow biopsy. In the most common form of leukemia in dogs, the lymphosarcomatosis, a bone marrow biopsy can be helpful in assessment of the prognosis.