Sperm output and hormone concentrations in Finn and Dorset rams exposed to long- and short-day lighting.

Seasonal changes in photoperiod have a substantial effect on sexual behavior and reproduction in rams. Little information is available on sperm output from high libido versus average libido rams subjected to intensive semen collection while being exposed to controlled short versus long photoperiods. Six Finn and six Dorset rams were compared in a reversal design, which allowed rams of both breeds to be exposed to 8 h versus 16 h of light. During each of two 84-d periods rams were subjected twice to an initial depletion of epididymal sperm reserves by collecting up to 26 ejaculates of semen in 3 d, followed by up to 10 ejaculates per day, 1, 3, 5, and 7 d after the initial depletion. A total of 2673 semen samples were collected. Nearly twice as many ejaculates (63.6% of the total) were obtained from Finn rams as from Dorset rams during both the initial and subsequent 3-d sperm depletion periods. This difference in libido was associated with obtaining 33.6 +/- 3.1 x 10(9) sperm from Finn rams versus 10.0 +/- 2.2 x 10(9) sperm from Dorset rams during the initial depletion period (P<0.05). Changes in photoperiod did not affect sperm output (P>0.05) in Finn rams, but may have affected Dorset rams. With 16 h of light, prolactin was significantly (P<0.05) increased in both breeds, particularly in Finn rams. Testosterone in both breeds followed an endogenous rhythm, not affected by the change in controlled photoperiods.

Freezability of spermatozoa from Finn and Dorset rams in multiple semen extenders.

Ten semen extenders were tested in two experiments for cryopreservation of semen collected from four Finn and four Dorset rams. Two ejaculates of semen were combined from each ram for testing each extender treatment. The extenders consisted of a series of commonly used egg yolk-TRIS media with and without sodium and triethanolamine lauryl sulfate (STLS), a similar extender with 3-N-morpholino propane sulfonic acid (MOPS), and milk and whey extenders. In Experiment 1, extender treatments were replicated with three sets of collections from the eight rams, and in Experiment 2 with two sets. The egg yolk-TRIS-glycerol-STLS (EY(1)TSTLS) extender was significantly superior to other extenders except whole milk in protecting the sperm during freezing and thawing. In Experiment 1, a 20% egg yolk-TRIS-glycerol-STLS extender preserved 71% of the progressively motile Finn sperm (post-thaw divided by pre-freeze percentage of motile sperm), and 76% of the Dorset sperm. In Experiment 2, the corresponding values for the same EY(1)TSTLS extender used with Finn and Dorset sperm were 86 and 64%, respectively. Without STLS the egg yolk extenders were significantly less effective in protecting cryopreserved ram sperm. This egg yolk-TRIS extender, containing STLS and glycerol, may hold promise for freezing ram sperm that could be used successfully for intracervical insemination.

Effect of rice cultivation on the prevalence and infection rates of Schistosoma intermediate host.

In this study, it was aimed to explore the effect of rice cultivation on the prevalence, density and infection rates on the snail intermediate hosts of human schistosomiasis. A village was chosen and examine for the main water canal supplying the rice field by making three successive scoops at 10.20, 30, 40 and 50 meters up stream the site of the pump supplying the rice field. The same was done in the large irrigation canal supplying 50 feddans of rice up to 100 meters (i.e. 10 sampling sites). Also the drains in between the rice fields were examined at 10 meters distance throughout the drain. The hunted snails were sorted, the Biomphalaria alexanderina and Bulinus truncatus were separated, their age was determined then crushed to look for immature stages under the microscope. Also the vegetations coming in the scoops were examined. The results showed that rice cultivation and irrigation is a suitable site for the prevalence and intensity of snails. Both species of snails were found in the main canal, irrigation canal and drains. All Bulinus truncatus snails were free from infections. The number of infected Biomphalaria alexanderina snails was significantly higher in the irrigation canal and drains than main canal which may be attributed to pollution of the drain water and irrigation canal by micturition and defecation or to the use of water in ablution.

1983 Nile Delta schistosomiasis survey: 48 years after Scott.

To determine whether the sharply declining Schistosoma haematobium infection rates in parts of the Nile Delta could be generalized to the entire region, and to update the status of S. mansoni infection rates, a large scale survey was undertaken in 1983 in 70 of the 71 districts of the Nile Delta. In a house-to-house survey, greater than 91% of the sample population of 16,675 participated by providing stool and/or urine specimens which were examined qualitatively by Kato thick smear and sedimentation techniques, respectively. After the 1935 survey by Scott, the prevalence of S. mansoni appeared to change little, from 33% in 1935 to 39% in 1983, but a more sensitive diagnostic technique in 1983 strongly suggested that the actual prevalence had decreased between the 2 surveys. In contrast, the prevalence of S. haematobium infection decreased from 56% to 5%, with a similar decline in all 8 governorates. The dramatic decline in S. haematobium prevalence has been accompanied temporally with a sharp decrease in the population density of Bulinus truncatus. S. mansoni has become the predominant human schistosome species in the Nile Delta.

Illness and reservoirs associated with Giardia lamblia infection in rural Egypt: the case against treatment in developing world environments of high endemicity.

A longitudinal investigation of the health effects and reservoirs of Giardia was undertaken during 1984-1985 in 40 households located in the rural Nile Delta region of Egypt. Stool specimens obtained once weekly for six months from 2-4-year-old children were cyst- or trophozoite-positive in 42% of the 724 examined. Only one child remained Giardia-negative during the study. The mean duration of excretion in Giardia-positive children was seven and one-half weeks with a range of one to 17 weeks. Mucus was present in 52% of all stools collected, and fecal leukocytes were observed with surprising frequency in the absence of identifiable pathogens. Clinical symptoms of illness were frequently observed within a month before or after Giardia excretion in stool of children, but a statistical inference of association was not demonstrated. Seventeen per cent of 697 specimens obtained from their mothers were Giardia-positive for a mean duration of four weeks and a range of one to 18 weeks. A total of 962 specimens were collected from 13 species of household livestock. Giardia was detected in 22 specimens from cows, goats, sheep, and one duck. Giardia cysts were detected in three of 899 samples of household drinking water. The ubiquity of the protozoan as well as the failure to show an association between infection and symptomatic illness argue against the administration of Giardia-specific drugs to children in settings where the risk of reinfection is high and for whom intestinal insults are both varied and constant.

The detection of enteropathogens in acute diarrhea in a family cohort population in rural Egypt.

In 8 villages of rural northeastern Egypt, a 2-year study of the etiologic agents associated with episodes of diarrhea was carried out. Stool specimens (3,243) from 3,513 episodes of diarrhea were processed for enteropathogens. The most commonly identified agents in the group with diarrhea were Giardia lamblia (44%), heat stable enterotoxin (ST)-producing enterotoxigenic Escherichia coli (ETEC) (15%), heat labile toxin (LT)-producing ETEC (12%), enteropathogenic E. coli (EPEC) (4%), rotavirus (3%), Shigella (2%) and Salmonella (1%). Isolation rates were increased in cases compared to controls for all agents except G. lamblia and EPEC strains. Rotavirus, Salmonella and ST-producing ETEC were more frequently isolated during cooler months and Shigella and LT-ETEC occurred more commonly in warmer months. Campylobacter, EPEC, Giardia and E. histolytica did not show a discernable seasonal pattern. Rotavirus was primarily associated with diarrhea in infants only. Forty-four percent of children experienced at least 1 bout of rotavirus diarrhea by the age of 3 years. Vomiting was reported in 65% of cases of rotavirus infection. Dehydration was reported in greater than 40% of those with rotavirus-, Salmonella-, Campylobacter-, LT-ETEC- and EPEC-associated illness and in those without an identifiable agent. While rotavirus was implicated in 3% of cases overall, when vomiting or vomiting plus dehydration occurred, rotavirus was identified with a rate of 10% and 12%, respectively. Dysentery was common only in Shigella cases, occurring in 24%. A decrease in occurrence of rotavirus, Campylobacter and possibly EPEC illness was seen in the infants less than 6 months of age who were breast-fed when compared to those who were not.

Risk of hepatitis B infection among Egyptians infected with Schistosoma mansoni.

Three hundred twenty-four individuals in a farming village located in the Nile Delta of Egypt were serially tested for hepatitis markers and Schistosoma mansoni to determine whether there is an increased risk of hepatitis B in persons infected with schistosomiasis. One-half of the subjects had stools positive for S. mansoni. Thirty-seven percent of the individuals had been infected with hepatitis B, and 3% were chronic HBsAg carriers. No statistical association was found between S. mansoni infection and hepatitis B infection, including chronic hepatitis B. Although there was no evidence of an association between these 2 pathogens, larger nonhospital based studies are needed to resolve this question.

The incidence of diarrheal disease in a defined population of rural Egypt.

A prospective study of diarrheal illness was conducted for 2 years in 309 families who were part of an epidemiologic research center population in rural Egypt. The rates of illness peaked in the first year of life with between 5 and 6 episodes per person year at risk. Although no seasonal variation in reported diarrhea was demonstrated for the total population, age-specific differences in seasonal occurrence were noted. The incidence did not consistently vary by village size, nor did rates vary by sex.

Immune responses and immunoregulation in relation to human schistosomiasis in Egypt. III. Immunity and longitudinal studies of in vitro responsiveness after treatment.

Immune responsiveness of schistosomiasis patients was assayed longitudinally, before and for two years after chemotherapeutic treatment with praziquantel, by in vitro peripheral blood mononuclear cell (PBMN) proliferation upon exposure to phytohaemagglutinin (PHA), or soluble schistosomal antigenic preparations from eggs (SEA), adult worms (SWAP) or cercariae (CAP). Parallel faecal and urine examinations documented the infection status of the patients during this time. Treatment resulted in substantially increased responsiveness to the schistosome-derived materials but not to PHA or C. albicans extract. The responses to SEA, SWAP, and CAP often remained elevated for one to two years after treatment. However, those patients who became reinfected had significantly lower PBMN responses to SEA or CAP at the time of the last blastogenesis assay before the observation that they were again stool-positive for Schistosoma mansoni eggs. No other demonstrable differences (such as age, sex, household location, pre-treatment intensities of infection or occupation) were observed between those who remained uninfected for at least two years (resistant?) and those who became reinfected during this time (susceptible?).

Immune responses and immunoregulation in relation to human schistosomiasis in Egypt. II. Cimetidine reversal of histamine-mediated suppression of antigen-induced blastogenesis.

The effect of histamine on cell-mediated immune responses of chronic schistosomiasis patients was tested by peripheral blood mononuclear cell (PBMN) reactions to phytohemagglutinin-P (PHA) and soluble schistosomal antigenic preparations derived from eggs (SEA) or adult worms (SWAP). PBMN responses to PHA were suppressed by exogenous histamine (10(-5)M), and the addition of cimetidine (CIM) (10(-4)M), an H2-receptor antagonist, reversed this suppressive effect. Histamine primarily suppressed PBMN responses to suboptimal and optimal PHA concentrations. Exogenous histamine (10(-5)M) also suppressed PBMN responses of 27 schistosomiasis patients to SEA and SWAP, respectively. The addition of CIM (10(-4)M) to suppressed cultures reversed the effect of exogenous histamine. Most importantly, the addition of CIM to schistosomal antigen-induced cultures, without exogenous histamine, significantly increased patients' PBMN responses to SEA and SWAP. The mean optimal increase in SEA responses of 19 patients was 390%. With SWAP-induced responses of 21 patients this increase was 165%. The use of 10(-4)M diphenhydramine (DPH), an H1-receptor antagonist, resulted in general suppression of both PHA-induced and schistosomal antigen-induced PBMN responses. Lower concentrations of DPH lead to variable responses but did not result in consistent abrogation of the histamine-induced suppression. These data imply that an histamine-induced, H2-receptor-mediated suppressor circuit often helps modulate antigen-specific responsiveness of PBMN from patients with chronic schistosomiasis.

An evaluation of quantitative techniques for Schistosoma haematobium eggs in urine preserved with carbolfuchsin.

The objective of this study was to determine a suitable method for quantitating Schistosoma haematobium eggs in urine specimens preserved in carbolfuchsin. Using a 0.002% carbolfuchsin-phenol-alcohol solution as a stain/preservative for urine obtained from 30 patients infected with S. haematobium, we compared egg counts obtained with four quantitative techniques: Nytrel filtration, Nuclepore filtration, suction filtration and centrifugation. Centrifugation gave statistically higher values than all other techniques for absolute number of eggs recovered in the preserved urine. We also measure a statistical difference between the counts obtained from Nuclepore filtration of fresh urine and those established on an equivalent volume of preserved urine by Nuclepore and Nytrel filtration. The preserved urine frequently caused obstruction of both Nuclepore filters and Whatman No. 1 filters (used in suction filtration), rendering them technically difficult to use and less satisfactory than other methods. From the techniques we examined, we conclude that in field studies where preservation of urine is necessary, preparation of Nuclepore filters with fresh urine, or centrifugation of a carbolfuchsin-preserved urine, are the methods of choice for quantitation of specimens.

Evaluation of natural killer activity in human schistosomiasis.

Natural killer (NK) activity was assayed in peripheral blood mononuclear cells of patients with schistosomiasis, of patients following treatment, and of uninfected control subjects. The patient populations were from villages in the Qalyub Province, Egypt and around Belo Horizonte , Brazil. NK activity was assayed by the cytotoxicity of 51Cr-labelled K562 target tumor cells. In neither infected population were significant alterations from normal levels found in the percent cytotoxicity per 10(6) cells, or in the lytic units that expressed 25% cytotoxicity. Likewise, prior treatment (2 and 6 months previously) did not alter the group NK activity detected. Similarly, in the Egyptian study there was no difference in the percentage of large granular lymphocytes between the infected and uninfected groups. In parallel studies in Egyptian and Brazilian schistosomiasis patients we did not find any evidence that this chronic infection consistently altered circulating NK activity.

The effects of indomethacin on in vitro peripheral blood mononuclear cell reactivity in human schistosomiasis.

The peripheral blood mononuclear cell (PBMN) proliferative responses of cells from patients with schistosomiasis were studied in the presence and absence of indomethacin in the culture medium. PBMN cultures were exposed to antigenic extracts of either adult S. mansoni worms (SWAP) or cercariae (CAP), and assayed for the incorporation of tritiated thymidine. More than 70% of the 48 patients studied with SWAP and the 40 patients studied with CAP, were not substantially effected by the addition of indomethacin to the cultures. The remainder (less than 30%) was augmented more than 50% by indomethacin and comprise a group which gave initially low responses to these antigenic preparations. Further analysis indicated that in some schistosomal patients the effect of an adherent suppressor cell population may, in part, be based on a prostaglandin-mediated, indomethacin-sensitive suppressive mechanism. However, the majority of patients, most of whom display adherent suppressor cells, are unaffected by indomethacin. Apparently, other adherent cell suppressor mechanisms are responsible for the regulation observed.

Immune responses and immunoregulation in relation to human schistosomiasis in Egypt. I. Effect of treatment on in vitro cellular responsiveness.

Cell mediated immune reactivity of chronic schistosomiasis patients was tested in vitro by peripheral blood mononuclear cell (PBMN) responses against phytohemagglutinin P (PHA), Candida albicans extract, soluble schistosomal antigenic preparations derived from eggs (SEA), adult worms (SWAP) and cercariae (CAP), before and after treatment of the patients with parziquantel. The patient population was from villages in the Qalyub province, Egypt, that are endemic for Schistosoma mansoni and S. haematobium. Patients were studied immediately before, and at 1, 3, 6, and 9 months after chemotherapy. Egg counts were done on stool and urine specimens taken simultaneously with blood samples. There was a significant increase in PBMN responses to SWAP and CAP but not to SEA, PHA or C. albicans in 27 patients (age 8-65) 1 month after treatment. Eleven patients treated 1.5 years previously did not show such elevated responses 1 month after re-treatment. Three months after treatment higher mean responses were observed to SWAP, CAP, SEA, and PHA, but not to C. albicans in 24 patients (age 6-26). Significant increases in PBMN responses to SWAP and CAP, but not to SEA, PHA or C. albicans were obtained at 6 months after treatment in 12 patients (age 6-30). By 9 months after treatment in a group of 11 patients (age 8-25) SWAP and CAP responses were still elevated as were SEA and C. albicans induced reactivities. The PBMN responses of 10 patients were followed longitudinally at pretreatment, 3-, 6-, and 9-month post-treatment times. In general, elevated responses were maintained throughout this period to the schistosomal preparations. Unrelated responses occasionally fluctuated but were not consistently altered over time.

Patterns of antischistosomal drug usage in Qalyubia Governorate of the Nile Delta.

To further investigate factors responsible for the recently documented changes in schistosomiasis patterns in the Nile Delta, questionnaire-derived information on antischistosomal drug usage was obtained from a 25% systematic sample of 609 residents of a stable village in the south-central Delta. Ten percent of the population had received antischistosomal drugs during the previous 4 years. Most of the drugs administered were injectable compounds, and 92% of individuals receiving them failed to complete the treatment regimen. Additional sources of information from a village physician, a pharmacist and a major pharmaceutical corporation confirmed and expanded the survey findings, indicating that antischistosomal drug usage cannot explain the recently observed changing patterns of human schistosome infections in the Nile Delta region.

Association of bacteriuria and urinary nitrosamine formation with Schistosoma haematobium infection in the Qalyub area of Egypt.

In Egypt, bladder cancer incidence is high in areas where the prevalence and intensity of Schistosoma haematobium infection is also high. Experimental evidence shows bladder carcinogenesis to be a multi-stage process which can be accelerated by many factors. N-nitroso compounds, some of which are known bladder carcinogens, can be formed from amine precursors and nitrate in urine during some bacterial infections. In experimental animals the growth of nitrosamine-induced urothelial cancers is accelerated by damage to the urothelium caused by S. haematobium infections, and by analogy in man this could account for the lower peak age of incidence of this cancer in Egypt by comparison with Europe. The present study was designed to investigate whether bacterial infection of the urinary tract was common in areas of endemic schistosomiasis and whether N-nitrosamines were regularly found to be associated with bacteriuria. Urine samples from young men in the Qalyub area of Egypt and from an adjacent Delta region were analysed for S. haematobium ova, the nature and intensity of any bacterial infection, nitrate and nitrite, and total N-nitroso compounds plus volatile N-nitrosamines. A relatively high prevalence of bacteriuria was found in young men with schistosomiasis and low levels of N-nitroso compounds were present in all specimens. When the groups were sub-divided on the basis of the ability of their bacterial flora to reduce nitrate to nitrite (the latter is required for the nitrosation of amine precursors to N-nitroso compounds), significantly higher levels of N-nitroso compounds were found in S. haematobium-infected individuals also infected with nitrate-reducing bacteria by comparison either with uninfected controls (p less than 0.0005) or with those infected with non-nitrate-reducing bacteria (p less than 0.001). The results show N-nitroso compounds to be present in the urines of young men in areas of endemic S. haematobium infection in Egypt, and elevated levels of urinary N-nitroso compounds to be associated with infection of the urinary tract by various species of nitrate-reducing bacteria.

Comparison of whole blood cultures and peripheral blood mononuclear cell cultures for evaluation of lymphocyte reactivity during chronic schistosomiasis.

Lymphocyte blastogenesis during chronic schistosomiasis has been evaluated previously by either whole blood or peripheral blood mononuclear cell (PBMN) culture techniques. These two methods were compared in the present study. Blastogenesis to the mitogen phytohaemagglutinin was greater in the whole blood cultures at the time assayed. Substantial antigen-induced lymphocyte transformation was elicited in both culture systems using cells from uninfected patients. However, patients' responses to schistosome-derived antigenic preparations as determined by whole blood culture were greatly reduced compared with PBMN cultures. In view of the known immunoregulatory activities associated with sera and cells from infected patients the whole blood technique may better reflect in vivo lymphocyte reactivity. The PBMN cultures are better suited to examine the immunoregulatory activities which may develop during this chronic infection.

Immunodiagnosis of infection with Schistosoma haematobium and S. mansoni in man.

We utilized the circumoval precipitin (COP) test, Ouchterlony immunodiffusion, and the enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of human infection with Schistosoma mansoni or S. haematobium, or with both species of schistosome. Only the COP test correctly identified all of those with schistosome infection, although differentiation as to schistosome species was impossible. Circumoval precipitates around S. haematobium eggs from human urine were more numerous and larger than those around S. mansoni eggs obtained from mouse livers. Ouchterlony immunodiffusion with S. mansoni or S. haematobium worm extract failed to diagnose correctly approximately one of every five infected individuals. Mean absorption values of the S. mansoni soluble egg antigen (SEA) used in the ELISA were similar in serum samples from persons infected with either or both species of blood flukes. This suggests that S. mansoni SEA is not species-specific. The ELISA correctly identified, however, 30 of 32 infected individuals, indicating high sensitivity.