COVID-19 and Corticosteroids: Unfamiliar but Potentially Fatal Infections That Can Arise following Short-Course Steroid Treatment

Corticosteroid use is increasing worldwide as recent studies confer survival benefit of corticosteroids in the management of patients with severe COVID-19. Strongyloides and amebic infections are neglected diseases that can progress to catastrophic complications in patients exposed to corticosteroids, even with short treatment courses. To prevent lethal outcomes, clinicians should be aware of the threat these two parasitic infections pose to at-risk patients receiving corticosteroids, especially in the era of COVID-19.

Recent Advances in the Discovery of Novel Antiprotozoal Agents

Parasitic diseases have serious health, social, and economic impacts, especially in the tropical regions of the world. Diseases caused by protozoan parasites are responsible for considerable mortality and morbidity, affecting more than 500 million people worldwide. Globally, the burden of protozoan diseases is increasing and is been exacerbated because of a lack of effective medication due to the drug resistance and toxicity of current antiprotozoal agents. These limitations have prompted many researchers to search for new drugs against protozoan parasites. In this review, we have compiled the latest information (2012-2017) on the structures and pharmacological activities of newly developed organic compounds against five major protozoan diseases, giardiasis, leishmaniasis, malaria, trichomoniasis, and trypanosomiasis, with the aim of showing recent advances in the discovery of new antiprotozoal drugs.

Parasitic Infections Associated with Unfavourable Outcomes in Transplant Recipients

Introduction. The immunosuppression used after transplantation (Tx) is associated with an increased risk of opportunistic infections. In Europe, parasitic infections after Tx are much less common than viral, bacterial and fungal ones. However, diseases caused by parasites are very common in tropical countries. In the last years the number of travellers with immunosuppression visiting tropical countries has increased. Methods. We performed a literature review to evaluate a risk of parasitic infections after Tx in Europe. Results. There is a real risk of parasitic infection in patients after Tx travelling to tropical countries. Malaria, leishmaniasis, strongyloidiasis and schistosomiasis are the most dangerous and relatively common. Although the incidence of these tropical infections after Tx has not increased, the course of disease could be fatal. There are also some cosmopolitan parasitic infections dangerous for patients after Tx. The greatest threat in Europe is toxoplasmosis, especially in heart and bone marrow recipients. The most severe manifestations of toxoplasmosis are myocarditis, encephalitis and disseminated disease. Diarrhoea is one of the most common symptoms of parasitic infection. In Europe the most prevalent pathogens causing diarrhoea are Giardia duodenalis and Cryptosporidium. Conclusions. Solid organ and bone marrow transplantations, blood transfusions and immunosuppressive treatment are associated with a small but real risk of parasitic infections in European citizens. In patients with severe parasitic infection, i.e., those with lung or brain involvement or a disseminated disease, the progression is very rapid and the prognosis is bad. Establishing a diagnosis before the patient's death is challenging.

Epidemiological and clinical picture of parasitic infections in the group of children and adolescents from north-east region of Poland

The epidemiological and clinical purview of parasite diseases is constantly evolving, mainly due to the changes in human behavior and our environment. The aim of this study was frequency analysis of certain parasite infections, risk factors and clinical symptoms in children and adolescents of north-eastern Poland. 120 children were tested due to the symptoms resembling parasite infection from December 2008 to May 2009. 90 patients (the tested group) aged from 5 months to 18 years were found to be infected with one or more than one of the following parasites: Ascaris lumbricoides, Giardia lamblia, Toxocara spp., Strongyloides stercoralis or Enterobius vermicularis. 30 children with no infections found were the control group. Parasites were found by means of microscope decantation stool tests, RIDA Quick Giardia stool test and ELISA blood test (Toxocara IgG). The patients' parents filled out the survey concerning the probability factors of infection and the ailments that were the cause of parasitical diagnosis. High percentage of either isolated or co-invasive parasite infections was ascertained in the tested group--75%. The prevalence of ascariasis was 55.83%, toxocariasis--16.67%, giardiasis--12.5%, strongyloidiasis--5.83% and of enterobiasis--3.33%. The statistical significance of higher dirty hands-mouth contact frequency and more frequent presence of domestic animals in the tested group than in the control group was ascertained. A highly important correlation between the infection and the occurrence of symptoms from at least 3 various systems was ascertained. The presence of habits involving dirty hands-mouth contact and having domestic animals are significant risk factors of parasite infections. The presence of symptoms from at least 3 systems should compel to parasite infection diagnosis with proper differential diagnosis.

Parasite zoonoses and wildlife: emerging issues

The role of wildlife as important sources, reservoirs and amplifiers of emerging human and domestic livestock pathogens, in addition to well recognized zoonoses of public health significance, has gained considerable attention in recent years. However, there has been little attention given to the transmission and impacts of pathogens of human origin, particularly protozoan, helminth and arthropod parasites, on wildlife. Substantial advances in molecular technologies are greatly improving our ability to follow parasite flow among host species and populations and revealing valuable insights about the interactions between cycles of transmission. Here we present several case studies of parasite emergence, or risk of emergence, in wildlife, as a result of contact with humans or anthropogenic activities. For some of these parasites, there is growing evidence of the serious consequences of infection on wildlife survival, whereas for others, there is a paucity of information about their impact.

Host-parasite kinship in a female-philopatric bird population: evidence from relatedness trend analysis

Conspecific brood parasitism (CBP), an alternative reproductive tactic where some females lay eggs in the nests of other females of the same species, occurs in many animals with egg care. It is particularly common in waterfowl, for reasons that are debated. Many waterfowl females nest near their birthplace, making it likely that some local females are relatives. We analyse brood parasitism in a Hudson Bay population of common eiders, testing predictions from two alternative hypotheses on the role of relatedness in CBP. Some models predict host-parasite relatedness, others predict that parasites avoid close relatives as hosts. To distinguish between the alternatives, we use a novel approach, where the relatedness of host-parasite pairs is tested against the spatial population trend in pairwise relatedness. We estimate parasitism, nest take-over and relatedness with protein fingerprinting and bandsharing analysis of egg albumen, nondestructively sampled from each new egg in the nest throughout the laying period. The results refute the hypothesis that parasites avoid laying eggs in the nests of related hosts, and corroborate the alternative of host-parasite relatedness. With an estimated r of 0.12-0.14, females laying eggs in the same nest are on average closer kin than nesting neighbour females. Absence of a population trend in female pairwise relatedness vs. distance implies that host-parasite relatedness is not only an effect of strong natal philopatry: some additional form of kin bias is also involved.

Nomenclature for parasitic diseases: cohabitation with inconsistency for how long and why?

The author surveys the early history of nomenclature for parasitic diseases or infections which led to the existing usage of synonymous names with diverse spellings for denominating the same disease entities. In order to diminish heterogeneity in nomenclatural usage, principles of the standardized nomenclature of parasitic diseases (SNOPAD) have been put forward by the World Association for the Advancement of Veterinary Parasitology. Pros and cons regarding the SNOPAD concept are discussed in seeking consensus terminology. The need for a standard nomenclature may be judged differently. SNOPAD is just a guideline based on carefully reasoned and clearly defined principles for those authors and editors dissatisfied with the existing heterogeneous and inconsistent nomenclatural usage and wish to rely on a uniform and standard disease nomenclature. The major suggestion of SNOPAD is the use solely of suffix -osis when disease name is coined from the name of a parasite taxon. Meanwhile, the proposed principles were found sensible and accepted more in the field of veterinary, less in medical parasitology. In a recent survey it has been revealed that the majority (73.8%) of 126 national language parasitological textbooks or compendia from 21 countries of Europe published since 1990 adopted consistent '-osis' disease terminology and the rest (26.2%) used a mixture of disease names ending in '-osis' and '-iasis' inconsistently. For achieving substantial shift towards the use of more consistent disease terminology, the interest and support of the parasitologists' community is required. Editorials and database producers hold the key to further progress provided they see the advantages of the use of a single name of worldwide currency for each disease entity.

The impact on database searching arising from inconsistency in the nomenclature of parasitic diseases

The existing usage of disease names formed from the name of the parasite taxon is characterised by marked heterogeneity. This is largely due to the fact that, for coining disease names, four different suffixes, '-osis', '-iosis', '-asis' and '-iasis', are being used inconsistently. The result is that alternative terms are in use for naming the same disease, e.g. trypanosomosis and trypanosomiasis, fasciolosis and fascioliasis, ascariosis and ascariasis. Inspite of the SNOAPAD/SNOPAD guideline (1988) which proposed the principles of a uniform and standard disease nomenclature, the actual usage depends largely on tradition, educational imprinting and personal preferences, showing great variation. By using alternative disease names as search terms the author investigates in four databases the impact of nomenclatural heterogeneity on information storage and retrieval. It is evident that the existence of alternative disease names in parasitology markedly interferes with the efficacy of online data retrieval. The value of a disease name as a search term was shown to be greatly different in various databases. Until we have to coexist with an inconsistent disease terminology we need to adopt specially structured database-search techniques to ensure a proper level of precision in searching. Such possible techniques are considered.

Effect of asymptomatic natural infections due to common mouse pathogens on the metastatic progression of B16 murine melanoma in C57BL/6 mice

To investigate whether the presence of infections in C57BL/6 mice influences the metastatic ability of B16 melanoma (B16M) cells, we compared the susceptibility to metastasis development of pathogen-free mice with that of mice from a colony endemically infected with several mouse pathogens. We found that, compared to seronegative controls, mice that were seropositive at least to Mouse Hepatitis Virus (MHV) and Mycoplasma pulmonis: (i) exhibited a higher interindividual variability in all the parameters quantifying metastatic progression; (ii) had elevated serum levels of proinflammatory cytokines both before and at the end of the experiment; (iii) were more susceptible to hepatic metastasis. Interestingly, final levels of tumor necrosis factor (TNF)-α and interleukin (IL)-18 correlated with the extent of hepatic colonization by the melanoma cells. To confirm the metastasis-enhancing effect of MHV and M. pulmonis we measured the ability of B16M cells to metastasize in pathogen-free animals housed for increasing time-intervals in the vicinity of MHV⁺ animals. Notably, susceptibility to metastasis was lower in animals seronegative to MHV than in MHV⁺ mice, whereas the latter were less susceptible to metastasis than MHV⁺M. pulmonis⁺ mice. Seropositive animals had increased levels of TNF-α and IL-18 suggesting that MHV and M. pulmonis enhance the metastatic ability of melanoma cells by inducing the release of proinflammatory cytokines. While our results highlight the importance of using pathogen-free animals in metastasis studies, they emphasize the need for a comprehensive health monitoring of the mice used in such studies, particularly in case of using facilities lacking appropriate containment measures.

Parasitic infections in Thai workers that pursue overseas employment: the need for a screening program

Stool examination is a requirement of the screening program for Thai workers seeking overseas employment. We report on the prevalence of intestinal parasitic infections among these workers; the stool examination results of 2,213 Thai workers who visited the Out-patients Department of the King Chulalongkorn Memorial Hospital between September 2000 and January 2001 were analysed. One hundred and thirty-five (6.1%) were found to be infected with 1 or 2 species of parasite. There were 54 (40%), 47 (34.8%), and 25 (18.5%) cases infected with nematodes, platyhelminths and protozoa, respectively. The commonest parasite was Opisthorchis viverrini (28.9%). Most nematode infections were due to Strongyloides stercoralis (19.2%); most protozoal infections were due to Giardia lamblia (17.0%). Mixed infections were found in 9 cases. Not unexpectedly, the rate of intestinal parasitic infection among Thai workers remains high. Screening for the parasitic infections among these workers can help to decrease their rate of rejection by the countries in which overseas employment is sought.

[The role of nitric oxide (NO) in parasitic infections]

Nitric oxide (NO) has been shown to play a crucial role in various physiological and pathological conditions. NO plays a role in the immunoregulation and it is implicated in the host non-specific defence in a variety of infections. Abundant evidence indicates that NO contributes to the host defence function of macrophages. High levels of NO are mediated by up-regulated expression of the iNOS gene in response to the activating signals, in particular to the secretion of pro-inflammatory cytokines (IFN-gamma, TNF-alpha, IL-1, IL-2) by Thl cells. In this review, the role of NO during a number of parasitic infections has been summarized. Up to now, enhanced levels of NO production and expression of iNOS gene have been described in such infective diseases as malaria, toxoplasmosis, leishmaniosis, trypanosomosis and schistosomosis. During these infections, the preferential production of pro-inflammatory cytokines predisposes to the increased synthesis of NO, which mediates host protection through either direct parasite killing or by limiting parasite growth. The evidence presented in this review supports the conclusion that NO plays an important role in the majority of parasitic infections.

Parasitic diseases of the heart

The following chapter is one of a series of chapters in the volume entitled Infections of the Myocardium appearing in Frontiers in Bioscience. The full table of contents can be found at http://www.bioscience.org/current/special/tanowitz.htm. In this chapter, we review several parasitic infections involving the myocardium and pericardium. The most widely studied parasitic infection affecting the heart is Chagas' disease or American trypanosomiasis. In this chapter we describe issues relating to Chagas' disease not covered in detail in other chapters. African trypanosomiasis may also cause a myocarditis. The protozoan parasite, Entamoeba histolytica rarely causes a pericarditis while Toxoplasma gondii may cause myocarditis, usually in immunocompromised hosts. The larval forms of the tapeworms Echinococcus and Taenia solium may cause space-occupying lesions of the heart. Severe infection with the nematode Trichinella spiralis may cause myocarditis.

[Forgotten parasitic diseases]

The ecological flexibility of parasitic systems is observed in parasites, such as pentastomas of Linguatula serrata and Armillifer sp., cestodes of Spirometra erinacei europaei, and dirofilariae of D. repens, D. immitis, D. ursi in relation to ecological shifts in the areas and anthropological pressure.

[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.

Seasonal prevalence of intestinal parasites in the United States during 2000

One-third of 5,792 fecal specimens from 2,896 patients in 48 states and the District of Columbia tested positive for intestinal parasites during the year 2000. Multiple infections with 2-4 parasitic species constituted 10% of 916 infected cases. Blastocystis hominis infected 662 patients (23% or 72% of the 916 cases). Its prevalence appears to be increasing in recent years. Eighteen other species of intestinal parasites were identified. Cryptosporidium parvum and Entamoeba histolytica/E. dispar ranked second and third in prevalence, respectively. Prevalence of infection was lowest (22-27%) in winter, gradually increased during the spring, reached peaks of 36-43% between July and October, and gradually decreased to 32% in December. A new superior method of parasite detection using the Proto-fix-CONSED system for fixing, transport, and processing of fecal specimens is described. In single infections, pathogenic protozoa caused asymptomatic subclinical infections in 0-31 % of the cases and non-pathogenic protozoa unexpectedly caused symptoms in 73-100% of the cases. The relationship between Charcot-Leyden crystals and infection with four species of intestinal parasites is examined and the list of provoking parasitic causes is expanded.

Current usage of nomenclature for parasitic diseases, with special reference to those involving arthropods

Terminological confusion has been aggravated by efforts to develop a standardized nomenclature for parasitic diseases (SNOPAD) arising from the proposal by Kassai et al., 1988) for a standardized nomenclature of animal diseases (SNOAPAD). To restabilize international nomenclature of parasitic diseases it is recommended that, whenever appropriate, names should follow the 'International Nomenclature of Diseases' (IND) compiled by the Council for International Organizations for Medical Sciences (CIOMS/WHO, 1987). For diseases not included in IND, familiarity should guide the choice of name: traditional English language names of diseases should be preferred, e.g. 'malaria', 'scabies' or, for parasitic diseases having no traditional name, the taxonomic name of the causative organism should be applied, e.g. 'Brugia timori microfilaraemia'; 'Plasmodium malariae infection'; 'Simulium allergy'--instead of the generic derivatives proposed by SNOPAD, i.e. brugiosis, plasmodiosis and simuliidosis, respectively. For names of new diseases or those rarely mentioned, the suffix -osis would normally take precedence. Generally, the name of choice for any disease in any language should be the vernacular term, with commonest English usage preferred for international communication, and publications should include synonyms in the list of keywords.

[Usefulness of the molecular techniques for detecting and/or identifing of parasites and fungi in humans and animals or pathogens transmitted by ticks (Part I)]

After a long period of using basic microscopic, immunological and biochemical methods for diagnosis, rapid development of nucleic acids investigation enabled introduction of specific and sensitive methods of detection of pathogenic agents on the molecular level. Among others, polymerase chain reaction (PCR), discovered in mid of 80'ies and then automatized, offered an attractive alternative to conventional testing systems. In this paper we describe reliable diagnostic tests widely used in the world, including Poland, and capable of detecting different disease agents as parasites and fungi in clinical specimens and pathogens of emerging zoonotic diseases in ticks. The possibilities of using molecular methods for determination of Plasmodium falciparum drug resistance is also discussed. Moreover, the report offers information concerning kinds of molecular tests and institutions in which there are executed.

[The evaluation of the military epidemiological importance of disease classes and its interpretation]

The article offers some new methods of disease classification for the Army and Navy medical service that will let them define the priorities in choosing the adequate measures for elimination and prevention of personnel losses due to infections, parasitic and other illness.

Environmental determinants of infectious and parasitic diseases

A review of the role of the environment as a determinant of infectious and parasitic diseases is presented. Historical considerations and the several environmental classifications of diseases are introduced. In a broader perspective the subject is analyzed in view of the emergence of the environmental health area, with its new paradigms. A review of epidemiological studies about environmental sanitation conditions and measures is presented, analyzing the conclusions derived from 256 studies. Finally, an epidemiological study carried out in Betim, Minas Gerais is briefly described, in order to illustrate the potentiality of this kind of study. Setting priorities of interventions regarding diarrhea control was the aim of this investigation. Conclusion about the role of this approach to optimize preventive measures for the control of infectious and parasitic diseases, of sound importance to the reality of the developing world, is stated.

[Investigations on the endoparasitic fauna of domestic cats in eastern Brandenburg]

The internal organs of 155 cats originating from 3 different territories in the eastern part of Brandenburg state were examined for parasites between 1993 and 1995. Parasites were found in 85% of cats. Parasites with the highest prevalence were Toxocara mystax (45%), Hydatigera taeniaeformis (22%), Ancylostoma tubaeforme (17%) and Opisthorchis felineus (16%). Metorchis bilis, Mesocestoides spp., Taenia pisiformis, Capillaria plica, Capillaria sp., Ollulanus tricuspis, Aelurostrongylus abstrusus, Cystoisospora spp. and Sarcocystis spp. were diagnosed with a lower frequency. The occurrence of H. taeniaeforme, A. tubaeformis und O. felineus was depending on the origin of the cats.

[Endoparasites of donkeys and horses kept in communal housing in Upper Bavaria; species spectrum and incidence]

In this epidemiological study of endoparasites 37 donkeys and 23 horses were included, which were examined coproscopically in regular intervals over a 15 month period. The animals derived from ten farms, in which regular prophylactic treatments with anthelmintics had been practiced at least for two years before this investigation. This study revealed the presence of at least twelve parasite species in donkeys, Eimeria leuckarti, Gasterophilus intestinalis, Fasciola hepatica, Anoplocephala perfoliata, Strongyloides westeri, Parascaris equorum, Dictyocaulus arnfieldi, Trichostrongylus axei and small strongyles, whose third stage larvae were characterized by eight, twelve, 16 or 18 intestinal cells. At least four parasite species were established in horses, E. leuckarti, G. intestinalis, P. equorum and small strongyles, whose third stage larvae were provided with eight intestinal cells. Infections with E. leuckarti, S. westeri and P. equorum were encountered in foals only and with D. arnfieldi in 16.2% of the donkeys. Incidences for small strongyles were highest, exhibiting neither age- and farm-dependent nor host species-dependent differences and amounting to 91.9% in donkey and 86.6% in horses. Considering all donkeys and horses, 35.1% and 43.5%, respectively, were infected at least with two, and 29.7% and 4.3%, respectively, with three parasite species. The species composition of the endoparasite fauna was always dominated by small strongyles. This field study indicates that the species composition of the endoparasite fauna in comparison to former investigations has not or only slightly changed in spite of widespread use of broad-spectrum anthelmintics for years. In addition, it has to be considered that donkeys continue to act as reservoir of D. arnfieldi and as source of infection for horses.

A hypermedia system for parasite identification

In this paper a hypermedia system for parasite identification is described. The knowledge base is relative to the class of the Trematoda parasites and reports agent, vector, disease, related category of the International Classification of Diseases and geographic area. A graphic user-friendly human-machine interface has been realized for this system.

100 years of delusional parasitosis. Meta-analysis of 1,223 case reports

Delusional parasitosis (DP) is mostly described in single cases or small samples. Data on epidemiology, nosological classification, therapy and course are therefore difficult to interpret. A thorough literature review is recommended to delineate common features of the syndrome. All case reports concerning DP (except toxic forms) were collected and analyzed according to a standardized protocol. DP is a disorder which may occur in every period of life but is much more frequent in older subjects. Sex differences with a predominance of females increase with age. Mean duration of delusion was 3.0 +/- 4.6 years (median: 1 year). Social isolation seems to be more a premorbid feature than a secondary phenomenon related to the delusion. Diagnostic classification revealed a high proportion of so-called 'pure' forms ('delusional disorders' in DSM-III-R or ICD-10) but the syndrome was also reported in schizophrenia, affective or organic psychosis or even as a neurotic symptom. Frequency of induced DP can be estimated between 5 and 15%. Course of DP is not so unfavorable as commonly thought; in about half the patients a full remission was described during the observation period or at catamnesis. Short preclinical courses may indicate better outcome. Comparing the patients of the prepsychopharmacological era (before 1960) with those after, the rate of full remissions increased from 33.9 to 51.9%.