Intestinal parasites: a study of human appendices

Histological sections of 414 appendices were examined parasitologically. Enterobius vermicularis was found in 8.7%, eggs of Ascaris lumbricoides in 0.5%, trophozites of Dientamoeba fragilis in 4.8%, Endolimax nana in 2.2%, Entamoeba coli in 1% and cysts of Giardia intestinalis in 1.9% of cases. Appendicopathies associated with Enterobius were most frequent in the age group from 6 to 10 years (24.3%) and from 21 to 25 years (12.2%). Patients older than 15 years were practically women only. Dientamoeba was most frequent in the age group from 11 to 15 years (11.3%). In women D. fragilis was three times more frequent than in men. The coincidence of D. fragilis and E. vermicularis infections was 50%. No interactions were seen between the protozoans in the contents of the appendix and its mucous membrane. Statistical evaluation indicates possible etiologic role of E. vermicularis in the occurrence of acute appendicities. D. fragilis appears to be the most common intestinal protozoan parasite in Bohemia.     

Entamoeba polecki: morphology, immunology, antigen study and clinic of the first infections in Czechoslovakia

Entamoeba polecki Prowazek, 1912 was recorded for the first time in Czechoslovakia in two students from Kampuchea. Uninucleated cysts of diameter 14.2-15.7 micron with nuclei diameter 3.2-4.2 micron were found-repeatedly in stool samples taken from them. The nucleus accounted in average for 24.3% of the cyst diameter. The isolation and two following subinoculations on Dobell-Leidlaw medium were achieved, more abundant growth was recorded on medium with pig serum. Sera of both students were positive in serological tests using the E. histolytica antigen. No serious clinical symptoms were observed, both patients were cured successfully by metronidazole and ornidazole. Electroimmunotransfer blots were used to characterize E. polecki as a separate species. The antigenic structure of polyxenically grown E. polecki was compared with the antigenic structure of E. histolytica (axenically grown HK-9 strain and 3 polyxenically grown strains). Different blot patterns of both species were obtained, but common fractions of 30-40 kD probably responsible for serological cross-reactions were found.     

Amoebiasis in foreign students

A total of 2,883 foreign students at the age of 18-30 years were examined for amoebiasis after their arrival to Czechoslovakia. Stool examinations revealed the presence of Entamoeba histolytica in 112 of them (3.9%). Students from 38 countries were found to be infected with this parasite. In a set of 2,064 students from these countries E. histolytica prevalence in stool was 5.4%. There were greater differences in the prevalence between individual countries inside a geographical region than between individual geographical regions. The highest E. histolytica prevalence in stool was found in students from tropical and southern Africa (6.7% of 745 examined) and the lowest in students from South-eastern Asia (3.1% of 321 examined). In a simple cross-section study, antibodies against E. histolytica were detected by enzyme-linked immunosorbent assay (ELISA) in the sera of 1,001 persons. Antibodies were detected in 7.9% of students at the following titres: 1:200 in 4.5%, 1:600 in 1.5%, 1:1,800 in 1.9%. Antibodies occurred more frequently in students carrying E. histolytica cysts (X2 = 14.9). Titre of ELISA antibodies in patients with confirmed liver abscess was higher than 1:1,800. counterimmunoelectrophoresis (CIEP) test was used for serum examinations of patients who had been demonstrated by ELISA to be seropositive and of those carrying E. histolytica cysts. In a set of 170 patients CIEP antibodies were also more frequent in those carrying E. histolytica cysts (X2 = 26.95). A comparison of the results of ELISA and CIEP tests in the same patients revealed that CIEP antibodies were more dependent on the actual parasitization with E. histolytica than ELISA antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum protein profile of mice during infection with single and repeated doses of Hymenolepis nana eggs

Significant alterations in serum protein of mice following Hymenolepis nana infection were observed. These changes were recorded as decrease in albumin, increase in gamma globulin and a temporary rise in alpha-1, alpha-2 and beta globulins. The decrease in albumin and increase in gamma globulin occurred as early as on 1st day after infection. The alpha-1 and alpha-2 globulins did not show definite profile during infection. The beta globulin predominantly increased till the day 20 post infection and thereafter generally decreased. Repeated infection did not enhance any further alterations in serum protein. There was no significant correlation between infection dose levels and serum protein changes.     

Gastrointestinal parasitoses discovered in agricultural workers in South Bohemia, Czechoslovakia

In the years from 1975 to 1982 1,750 persons, mostly employed by agricultural enterprises in the South Bohemian Region in Czechoslovakia, were examined. We discovered seven species of parasites: Taenia saginata in 0.3%, Enterobius vermicularis in 10.1%, Giardia lamblia in 1.0%, Endolimax nana in 0.8%, Entamoeba coli in 0.7%, Entamoeba hartmanni in 0.2%, and Chilomastix mesnili in 0.5%. The greatest number of parasites was found in students of the Secondary agricultural and technical school. Only two species of parasites were diagnosed in children of the employees. The incidence of E. vermicularis was 75% in children, in adult employees of agricultural enterprises, however, only 9.8%.     

Three new helminth species from two endemic plethodontid salamanders, Typhlomolge rathbuni and Eurycea nana, in central Texas

Helminthological examination of two rare, endemic species of plethodontid salamanders, the Texas blind salamander (Typhlomolge rathbuni Stejneger) and the San Marcos dwarf salamander (Eurycea nana Bishop), from the subterranean waters and springs in San Marcos, Hays County, central Texas, USA revealed the presence of three new, previously undescribed species of intestinal helminths: Brachycoelium longleyi sp. n. (Trematoda) from T. rathbuni (type host) and E. nana, Dendronucleata americana sp. n. (Acanthocephala) from T. rathbuni, and Amphibiocapillaria texensis sp. n. (Nematoda) from T. rathbuni; nematode larvae probably belonging to the last named species were recorded from E. nana. Brachycoelium longleyi can be distinguished from all congeners primarily by its conspicuously small eggs among other features, whereas A. texensis differs from its closest congeneric species A. tritonispiunctati mainly in the structure of mature eggs and a markedly shorter spicule. Dendronucleata americana is the first species of the family Dendronucleatidae from the New World, differing from its Asian congeners mainly in the number and arrangement of proboscis hooks, number of giant hypodermic nuclei and in the position of testes.     

Entamoeba histolytica: surface proteolytic activity and its relationship with in vitro virulence.

We determined the surface-associated proteolytic activity in three Entamoeba histolytica Schaudinn, 1903 strains (monoxenic HM1, axenic HM1, and HK9) of known virulence and its relationship with collagenase activity. Both activities were also determined in axenic HM1 amoebae trophozoites which were sensitive and resistant to complement-mediated lysis. Surface proteolytic activity was determined in glutaraldehyde-fixed E. histolytica trophozoites, which degraded the insoluble substrate, hide powder azure, and cleaved the human immunoglobulin G heavy chain in a time-dependent fashion, at neutral pH, in presence of 2-mercaptoethanol as cysteine protease activator. Surface proteolytic activity was strain dependent: monoxenic HM1 > axenic HM1 > axenic HK9. This activity correlated with collagenolytic activity (p < 0.05). Acquisition of resistance to complement-mediated lysis by axenic HM1 strain did not modify either surface proteases or collagenase expression. Our results suggest that this surface proteolytic activity could be used as an in vitro virulence marker for E. histolytica.     

Histopathological diagnostics of liver amoebiasis in Cambodia

Results of histopathological examination of a solitary chronical amoebic abscess in the liver of a patient from Cambodia are described. The abscess was at a proliferously reparative phase and Entamoeba histolytica was detected at the border between the necrosis and inner wall of abscess, as well as in the proper non-specific granulation tissue of the inner layers of abscess capsule. A differential diagnosis of the amoebic abscess from similar parasitary or pseudoparasitary liver lesions and differential diagnosis of amoebae in histological sections are given. For orientation examinations of the liver tissue for the presence of amoebae the authors recommend the impregnation after Grocott and staining with Goldner's trichrome for a more detailed evaluation of histological sections.     

Entamoeba histolytica--the virulence of imported strains

We tested the virulence of 15 strains of Entamoeba histolytica, imported to Czechoslovakia, by intracaecal inoculation of laboratory rats. According to the scoring system of Neal, none of the 15 strains possessed the virulence index greater than 2. This indicates that all the organisms tested should be classified as avirulent. However, it should be noted that all the strains produced infection of the caecum and thus should be considered infective for rat. For 7 strains, isoenzyme patterns were determined for PGM, HK and ME. One imported strain, obtained from student from Congo, demonstrated isoenzyme pattern for PGM and HK indicated that the strain was virulent. This organisms had the index of virulence 1.8 (avirulent) in animal experiment; it was isolated from cysts of clinically asymptomatic patient. Examination of the rectal mucosa of the donor of the strain indicated typical chronic catarrhal proctitis of mild degree. Examination of the patient's serum demonstrated the presence of anti E. histolytica antibodies by CIEP, while the ELISA test was negative. Twenty-one cyst carriers were examined by rectoscopy. Pathologic changes were observed in 20 of these, as follows: altered vascular structure (13X), roughened mucosa (12X), mucosal reddening (10X), decreased glistening (7X), mucus in mucosa (5X), inflammatory pseudopolypes (2X), ulcers (2X), enanthema (1X). Histological biopsies were obtained in 15 cases. One was considered normal. Remaining 14 biopsies exhibited following morphological changes: increased mucus secretion (8X), edema (7X), lymphocytic and plasmocytic infiltration (6X), lymphocytic and plasmocytic infiltration in addition to the presence of eosinophilic granulocytes (6X), presence of mucophages (5X), haemorrhages (4X), increased vascularity (3X), lymphocytic and plasmocytic infiltration with presence of extremely abundant eosinophilic granulocytes (1X), erosive-ulcerative changes of mucosa (1X). The changes observed indicated chronic catarrhal proctitis with expression to greater or less degree of signs of chronic catarrhal inflammation.     

Analysis of intestinal intraepithelial lymphocyte populations in experimental Trichinella spiralis infection of mice

The potential role of intestinal intraepithelial lymphocytes (i-IELs) in the generation of host protective immunity after helminth infection was investigated using the Trichinella spiralis (Owen, 1835)/mouse model. In this study we found a significant rise of TCRgamma(delta)+ i-IELs (P < 0.001) concurrent with the jejunal goblet cells (GC) hyperplasia in T. spiralis-infected C57BL mice on day 4 p.i. However, no direct relationship between the kinetics of the increase in TCRgamma(delta)+ i-IELs and T. spiralis expulsion was observed in infected mice. Taken together, these results implicate that gamma(delta) i-IELs probably perform a unique functions related to the regulation of the GC proliferation accompanying T. spiralis gut infection. As is known, these TCRgamma(delta)+ i-IELs may release mediators or growth factors that in turn influence GC differentiation. With the use of dexamethason (DEX), a potent anti-inflammatory agent which also induces apoptotic cell death in i-IELs, we have confirmed that the expulsion of T. spiralis from the mouse gut is accompanied by an inflammatory response. Indeed, the GC are clearly involved in these phenomena, apparently under the regulation by TCRgamma(delta)+ i-IEL-mediated responses, since DEX abrogated GC proliferation in T. spiralis-infected C57BL mice and subsequently augmented adult worm burden. Our data also show that the rejection of adult worms starts concurrently with a significant increase in TCRalpha(beta)+ and CD8+ i-IELs (P < 0.05 and P < or = 0.01, respectively), namely by day 7 p.i. At the same time, CD4+ cells significantly decreased (P < 0.05) in the intestinal epithelium of T. spiralis-infected, vs uninfected mice. These results may indicate that the TCRalpha(beta)+ and CD8+ i-IELs act as effectors of anti-T spiralis defence reactions. The implications of these findings for the potential role of intestinal intraepithelial CD8+ and TCRalpha(beta)+ cells in the pathogenesis of the intestinal lesions during T. spiralis gut infection are discussed.     

Malaria in the province of Takeo, Cambodia

Malaria was studied in the province of Takeo, Cambodia. In the hyperendemic region of Kirivong district, 49 (46.0%) of 105 suspected patients were found to be infected, 98% of them with Plasmodium falciparum and 2.0% with P. vivax. The highest prevalence (85.7%) was recorded in the group of 15-20-year-old patients. A total of 296 patients were examined in the hospital of Takeo during one year (1983-1984) and 77 (26.0%) of them were positive. P. falciparum infection was found in 76.6% and P. vivax in 23.4% of cases. The highest prevalence (42.3%) was also in the age-group of 15-20 years. The "7-day test" was used in vivo in 15 patients in order to detect the sensitivity of P. falciparum to Fansidar. The asexual forms of parasites disappeared within 4 days, while the gametocytes survived in two patients until 7th and 8th day, respectively. The observations could not be terminated, since the two patients will fully left the hospital.     

Circulation of mosquito-borne viruses in large-scale sheep farms in eastern Slovakia

Samples of blood sera collected from 608 sheep in large farms of the districts of Trebisov, Michalovce, Vranov nad Toplou and Humenné were investigated in hemagglutination-inhibition test for the presence of mosquito-borne viruses Sindbis, West Nile, Tahyna and Calovo. Antibodies to arboviruses Tahyna (11.5%) and Calovo (10.9%) were detected most frequently, while a lower sero-positivity was recorded to the Sindbis (2.3%) and West-Nile (1.0%) viruses. Certain differences were found in the infection rates in the respective districts: the highest frequency of antibodies to Tahyna and Calovo viruses was recorded in sheep of the district of Trebisov and the lowest one in animals of the district of Humenné.     

Synthesis and anthelmintic activity of thioamide analogues of cyclic octadepsipeptides such as PF1022A

The tetra- and mono-thionated cyclic octadepsipeptides represent novel cyclic octadepsipeptide derivatives with broad-spectrum activity against parasitic nematodes in mice and sheep. Some of these show better activity than the potent natural anthelmintic cyclic octadepsipeptide PF1022A against Hymenolepis nana, Heterakis spumosa and Trichinella spiralis larvae in mice. In particular, they show improved efficacy against Haemonchus contortus and Trichostrongylus colubriformis in sheep compared with PF1022A. Here we report on two different and simple synthetic pathways for this new class of thionated cyclic octadepsipeptides.     

Isolation of Microdochium oryzae and Pinatubo oryzae from Rice Seeds and their Survival on Stored Seeds

The aim of these studies was to develop a semi-selective medium to differentiate Microdochium oryzae and Pinatubo oryzae, determine the frequency of seed infection of M. oryzae, study survival of the pathogen in stored seeds, and determine the frequency of infection of seed components. To simulate epidemics of differing intensities, panicles of rice cultivars that are susceptible (IR36) and resistant (IR42 and IR46) to M. oryzae were either non-inoculated, inoculated once, twice, or three times with a conidial suspension of M. oryzae. Both M. oryzae and P. oryzae colonies were recovered from seeds and were similar in culture. A semi-selective medium developed to detect M. oryzae seed infection rates aided in differentiating M. oryzae and P. oryzae by stimulating aerial conidiogenesis of P. oryzae. The conclusions taken from these results were: (a) seeds of IR36 had higher infection of M. oryzae than of IR42 and IR46 from plants grown in the dry season, but had lower infection of M. oryzae than of IR42 and IR46 from plants grown in the wet season; (b) M. oryzae infected seeds increased with an increase in the epidemic intensity with the highest occurring after three inoculations, the least occurring with non-inoculation, and intermediate with one, or two inoculations; (c) survival of M. oryzae decreased over time in seed lots stored at 10°C and 40% relative humidity and (d) all components of the rice seeds of IR36, IR42 and IR46 lots were infected with M. oryzae with the highest frequency in the endosperm and lemma, intermediate in the basal glumes and palea, and the least in the embryo.     

Intestinal helminthic infections of cats in Calabar, Nigeria

A study of intestinal helminthic infections of 52 cats (Felis catus) was undertaken in Calabar, Nigeria. Direct smear and zinc sulphate floatation technique were utilized. The following helminths were observed: Toxocara cati (28.85%), Ancylostoma tubaeforme (19.23%), Trichuris felis (5.77%), Dipylidium caninum (23.08%) and Taenia taeniaeformis (9.61%). The worm burdens were generally low, ranging from 2 to 20 per cat. No definite pattern of infection was observed with regard to sex. Trematodes were not seen. The zoonotic and public health aspects of some of these helminths are discussed.     

Cucumber mosaic cucumovirus incidence in open‐field tomato in the Olympia area and trap captures of alate aphids*

Cucumber mosaic cucumovirus (CMV) has been the most serious pathogen of tomato in Greece for the last 15 years, causing tomato shrinkage, tomato necrosis and tomato fruit necrosis. In an epidemiological study in Eleia county, one of the main centres of production of processing tomato in Greece and one most affected by CMV, it was confirmed that the virus had an extremely high frequency. Disease frequency and severity was found to have a patchy spatial and temporal distribution at county, zone and locality level, during the years and within 1998, the main year of experimentation (and a disastrous year for CMV). Great variation was found in the trends of infection frequencies during the growing season of 1998 in the 15 experimental fields but all were finally 100% or almost 100% infected. The trends of infection frequency in these 15 fields paralleled total captures of alate aphids by a Rothamsted‐type trap, whereas in one of these fields, with a Moericke‐type trap, these parallel captures were composed almost exclusively of Aphis spiraecola.     

Evaluation of diagnostic and quantitative PCR for the identification and severity assessment of eyespot and sharp eyespot in winter wheat

Diagnostic and quantitative polymerase chain reaction (PCR) provided clarification of the causes of symptoms and the extent of infection by eyespot ( Tapesia spp.) and sharp eyespot ( Rhizoctonia cerealis ) on winter wheat at early growth stages. Disease assessments made before stem extension, when decisions to apply fungicides are usually made, often did not agree with the pathogen diagnoses using PCR, suggesting that such early visual diagnoses may be unreliable. Visual and PCR diagnoses made on stems in summer generally supported each other, but there were often discrepancies in relating disease severity to amounts of pathogen present when determined by regression analyses of incidence or severity of symptoms on amount of pathogen DNA. Mixed symptoms caused by different pathogens may sometimes have been confounded. Relationships between symptoms and DNA of eyespot pathogens were less clear on some cultivars, often those with least disease. Sharp eyespot symptoms had a stronger relationship to DNA of its pathogen. Significant regressions often accounted for a small percentage of the variance, suggesting either that pathogens not assayed were contributing to symptoms or that lesions were in some cases persisting longer into the season than pathogen DNA. The frequency of pathogen detection before stem extension was a poor predictor of the amounts of pathogen DNA measured later in the season.     

Experimental infection of immunocompetent and immunodeficient mice with Encephalitozoon cuniculi

An experimental infection with the microsporidian Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 was studied using a model of immunocompetent BALB/c mice and immunodeficient SCID mice. The course of infection after intraperitoneal inoculation of E. cuniculi spores was evaluated using the presence of spores in peritoneal macrophages as a criterion. First significant decrease in the proportion of infected cells was recorded on day 9 post infection (p.i.) in BALB/c mice. From day 14 p.i. no spores were observed in macrophages from BALB/c mice, while the number of infected macrophages from SCID mice increased until the death of the mice. The natural killer (NK) cell activity of mouse splenocytes was compared with the production of interferon gamma (IFN-gamma) by these cells. While in BALB/c mice NK activity peaked on days 9 and 14 p.i., in SCID mice the marked increase of NK activity was recorded close before death of mice, on day 21 p.i. in correlation with the production of IFN-gamma. Production of specific antibodies was demonstrated from day 9 p.i. in sera from BALB/c mice. It is concluded that intraperitoneal infection of SCID mice with spores of E. cuniculi results in the marked increase in the number of peritoneal exudate cells and in the percentage of infected cells close before death of mice. Neither high activity of NK cells nor increased production of IFN-gamma are sufficient for the recovery of SCID mice from an E. cuniculi infection.     

Genetics of Host Specificity in Epichloë typhina

ABSTRACT Epichlo? typhina perennially and systemically infects grass plants, causing choke disease in which maturation of host inflorescences is suppressed. In seedling-inoculation tests, isolate E8 from perennial ryegrass established and maintained infection in this host but not in orchardgrass. In contrast, isolates E469, E2466, and E2467 from orchardgrass varied in infection frequency and stability in orchardgrass, but all were unable to establish stable infections in perennial ryegrass. To investigate the genetics of host specificity, isolate E8 was crossed with each of the isolates from orchardgrass. Seedlings of parental host species were inoculated with F(1) progeny, and the frequencies of seedling infection and stability in adult plants were assessed. In the E8 x E2466 cross, the F(1) progeny exhibited a wide range of infection frequency and stability in each parental host. In crosses E8 x E469 and E8 x E2467, where the orchardgrass-derived parents infected 5 to 13% of inoculated perennial ryegrass seedlings, the distributions of infection frequencies for the F(1) progeny wereskewed toward levels comparable to that of the parent from perennial ryegrass. In all crosses, most progeny had low frequencies of infection in orchardgrass. However, transgression was evident in a cross of E8 with E469, an isolate that infected orchardgrass seedlings at a low frequency (2 to 3%). The E8 x E469 cross had a few F(1) progeny that infected orchardgrass at high efficiency (up to 81%). A Spearman rank correlation applied to the E8 x E2466 progeny indicated a significant negative correlation between infection frequencies in perennial ryegrass and orchardgrass. Also, there was a significant correlation of infection frequency and stability in perennial ryegrass but not in orchardgrass. To test whether only a few genes governed infection frequency in perennial ryegrass, an E8 x E2466 F(1) progeny (designated E386.04), which had intermediate compatibility with this host, was backcrossed to E8. The progeny of this backcross exhibited a distribution of infection frequencies in perennial ryegrass between that of E386.04 and the backcross parent, suggesting that multiple genes may determine compatibility at the seedling infection stage. The results of these experiments indicated multiple genetic determinants of compatibility or incompatibility with each host, with intermediate or high heritability.     

金龟子绿僵菌对石蒜绵粉蚧的室内毒力与防治效果

石蒜绵粉蚧是近年我国新记录的一种有害生物,目前在福建省漳州地区的多肉植物种植基地发生为害严重。为探讨金龟子绿僵菌F061和FM-03对该虫的生防潜力和应用前景,本研究测定这2株菌株对石蒜绵粉蚧的室内毒力和防治效果。结果表明,石蒜绵粉蚧受菌株F061和FM-03侵染10 d后1×10⁸孢子/mL处理浓度的累计校正死亡率分别为83.15%和91.95%;构建的2个TDM模型均通过Pearson卡方和Hosmer-Lemeshow检验,2株菌株对石蒜绵粉蚧的时间-剂量互作效应明显,剂量效应随侵染时间的延长逐渐升高,时间效应随菌液浓度的升高逐渐增强,菌株F061侵染10 d后的LC₅₀和1.00×10⁸孢子/mL处理的LT₅₀分别为5.55×10⁵孢子/mL和5.04 d,而菌株FM-03在同等条件下的LC₅₀和LT₅₀分别为1.11×10⁵孢子/mL和4.67 d,毒力强于菌株F061;此外,2株菌株1.00×10⁸孢子/mL处理浓度对石蒜绵粉蚧的室内防治效果也随试验时间的延长而提高,菌剂F061和FM-03喷施10 d后的室内防治效果分别为74.06%和81.32%。综上,2株菌株均可用于防控多肉植物上的石蒜绵粉蚧,菌株FM-03可优先开发应用,菌株F061可作为备选菌株使用。