The occurrence of Schistosoma mattheei in the south-western Transvaal

To determine whether Schistosoma mattheei is present in the south-western Transvaal, sixty habitats were searched for the intermediate host snail, Bulinus africanus. Ten populations of this snail were located, 2 of which were infected with S. mattheei. Eggs of one of these isolates, originating from a spring in the Mooi River, were examined with an optical microscope. Scanning electron micrographs of the teguments of adult male worms and the terebratorial membranes of miracidia are described. These parasites are morphologically similar to some previously described from another habitat in the same geographical area and both populations can be regarded as typical S. mattheei.     

An experimental Schistosoma mattheei infection in man

Certain aspects of the immune response of a male experimentally infected with 3-day old cercariae of a pure field strain of Schistosoma matheei were investigated. Among others, aspects such as the reaction of eosinophils, neutrophils and blood platelets after infection, were included in the study. The involvement of IgG and the cross reaction between these antibodies and S. haematobium and S. mansoni were also investigated. The phenomenon that the cercariae were, 3 days after shedding, still capable of penetrating the skin causing an inflammatory response was studied. The results lend some support to the surmise that a pure S. mattheei infection in humans is incapable of any egg production.     

Schistosoma mattheei in the ox: clinical pathological observations

Twenty-eight Friesian calves were infected between seven and 11 months of age with 5000 to 45,000 cercariae of Schistosoma mattheei. They developed anaemia, lymphopaenia and hypoalbuminaemia during the period of acute clinical illness after the infection became patent, and lymphocyte counts remained depressed after clinical recovery. Neutrophil counts rose and later fell before returning to normal. Eosinophilia and hypergammaglobulinaemia were marked during the period of recovery. The changes in haemoglobin, neutrophils and serum proteins were proportional to the level of infection. The eosinophil response was reduced in animals subjected to nutritional stress. The aetiology of the changes is discussed.     

Schistosoma mattheei in the ox: the serological response

Thirty Friesian steers were infected with Schistosoma mattheei and the antibody response was followed for up to 76 weeks by the complement fixation (CF), indirect haemagglutination (IH) and indirect immunofluorescent (IF) tests. CF and IF antibodies rose to a peak at about 25 weeks and then fell, while IH antibodies rose more slowly and remained high. Peak IH and IF titres were proportional to the level of infection. Peak CF titres were reduced in animals on a low plane of nutrition. There was a strong cross-reaction to Fasciola gigantica and Paramphistomum microbothrium in the CF test while the IH and IF tests were specific. The IF test proved of value in the diagnosis of naturally occurring clinical schistosomiasis.     

Further observations on an intratubercular sensory receptor of Schistosoma mattheei

A structure, presumably a sensory receptor in the nippled tubercles of Schistosoma mattheei, previously observed by scanning electron microscopy, was studied further by light and transmission electron microscopy. The results obtained by differential staining indicate that this structure does, in fact, consist of nervous tissue, and this provides additional evidence to support the sensory receptor hypothesis.     

Placental transfer of immunoglobulins in cattle infected with Schistosoma mattheei

Although the epitheliochorial placenta of ruminants does not allow passage of immunoglobulins from dam to foetus specific antibodies have been detected at birth in calves born to Schistosoma mattheei-infected cows. The present study determined the prevalence of calves born with specific antibodies for S. mattheei and the origin of these antibodies. For the determination of the prevalence, 100 calves born to infected mothers in an endemic area (Zambia) were examined, 24 were seropositive. To study the origin of these antibodies placentomes of 40 naturally S. mattheei-infected cows were examined for the presence of schistosome eggs and lesions which could explain foetal priming and/or leakage of maternal antibodies and/or antigen into the foetus. Tissue damage and schistosome eggs were observed on the maternal as well as the foetal side of the placentomes. In order to determine the specific nature of the antibody response, antibody profiles against soluble adult worm antigen preparation (SWAP) of S. mattheei were compared by Western blot between dams and their newborn calves (n = 8). The specific recognition profiles were identical for the seropositive calves and their dams on SWAP mattheei. Identical recognition profiles between dams and calves were also observed when sera were analysed on Escherichia coli, a pathogen of which the foetus should be free, and would indicate passive antibody transfer from the dam. In conclusion, the present study shows that S. mattheei could induce placentome lesions and that eggs can cross the placenta. Consequently, foeti can come into contact with S. mattheei antigens in utero, and might also contain maternal antibodies from leakage through placentome lesions. As such, the infection status of the mother could have far reaching effects on the immunological status of her offspring and modify their reaction upon infection.     

Enzyme electrophoresis of South African Schistosoma mattheei and S. haematobium

As a pilot project of a study undertaken to determine the influence of S. mattheei X S. haematobium hybridization on various South African S. mattheei populations by means of biochemical-taxonomic methods, a comparative electrophoretic study of laboratory-maintained S. mattheei and S. haematobium was performed, using 11 enzymes representing 16 gene loci. Eleven loci were found to be monomorphic, while 5 differed interspecifically. Computation of the results revealed that South African S. mattheei and S. haematobium are fairly closely related when compared with other Schistosoma spp. groups.     

Further observations on the electrophoretic characterization of South African Schistosoma mattheei and S. haematobium

Eleven enzymes, which were used to compare South African S. mattheei and S. haematobium in a former study, were employed to study intraspecific variation within S. mattheei, using starch gel electrophoresis and iso-electric focusing where resolution in starch gel was poor. Acid phosphatase varied intraspecifically within S. mattheei in that the most southern population differed from the northern populations. Malate dehydrogenase also varied intraspecifically. Three populations which occur sympatric with S. haematobium had a MDH-1 allele in common with the human schistosome while an allopatric population did not.     

The morphology of a sensory receptor in the nippled tubercles of Schistosoma mattheei

During scanning electron microscopy (SEM) of the tegument of Schistosoma mattheei, a structure was observed within the nippled tubercles. It is postulated that it is a sensory receptor with a tactile function.     

Scanning electron microscopy of the teguments of males from five populations of Schistosoma mattheei

The teguments of males from 5 populations of S. mattheei, of which 3 were sympatric and 2 allopatric with S. haematobium, were studied by means of scanning electron microscopy (SEM). A certain percentage of the males of each sympatric population bore tubercle spines while the allopatric populations were spineless. It is postulated that the presence of tubercle spines is a characteristic inherited from S. haematobium.     

Phenotypic differences in Schistosoma mattheei ova from populations sympatric and allopatric to S. haematobium

Schistosoma mattheei ova were collected from cattle in different localities in South Africa and after hatching, miracidia were used to infest Bulinus (Physopsis) globosus. Cercariae harvested from these snails were used to infest the definitive host Praomys (Mastomys) coucha and eggs from the resulting female S. mattheei were collected. These ova were compared with a Schistosoma haematobium X S. mattheei hybrid similarly collected from an infested P. (M.) coucha. The results indicate that S. mattheei populations which are sympatric to S. haematobium possess S. haematobium characteristics. It is suggested that the gene pools of populations of the parasite in these areas are infiltrated with S. haematobium genes via the S. mattheei X S. haematobium hybrid originating from human hosts.     

The influence of colostrum on infection of calves around 7 months of age with Schistosoma mattheei

Thirty red-legged partridges (Alectoris rufa), 5-month-old, were orally inoculated with oocysts of the OV-51/95 strain of Toxoplasma gondii. Birds were distributed into five groups and received, respectively, 10 (group A, 4 birds), 50 (group B, 14 birds), 10(2) (group C, 4 birds), 10(3) (group D, 4 birds) and 10(4) (group E, 4 birds) oocysts. One partridge from group B and one from group E died suddenly of acute toxoplasmosis at 7 day after inoculation (DAI) with demonstrable T. gondii in several tissues. The rest of birds remained clinically normal until killed at 44, 58, 65, 72, 79 or 100 DAI. Brain, heart, liver and skeletal muscle from these partridges were bioassayed individually in mice; T. gondii was demonstrated in all these tissues, except in heart of three birds inoculated, respectively, with 10, 50 and 10(2) oocysts. Lesions were not seen in histologic sections of tissues from surviving partridges. These results suggest that red-legged partridges are resistant to clinical toxoplasmosis.     

Epidemiological studies of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

During the period between January 1999 and December 2000, the distribution and seasonal patterns of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Faecal samples of cattle were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined at monthly intervals from November 1998 to October 2000, a period of 24 months, in six dams and six streams in the highveld and nine dams in the lowveld communal grazing areas. Monthly, each site was sampled for relative snail density, the vegetation cover and type, and physical and chemical properties of the water. Mean monthly rainfall and temperature were recorded. Snails collected at the same time were individually examined for shedding of cercariae of S. mattheei and Schistosoma haematobium. A total of 16264 (5418 calves, 5461 weaners and 5385 adults) faecal samples were collected during the entire period of study and 734 (4.5%) were positive for S. mattheei eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), calves compared to adult cattle (P < 0.01) and the wet season compared to the dry season (P < 0.01). Faecal egg output peaked from October/ November to March/April for both years of the study. Bulinus globosus, the snail intermediate host of S. mattheei was recorded from the study sites with the highveld having a significantly higher abundance of the snails than the lowveld (P < 0.01). Monthly densities of B. globosus did not show a clear-cut pattern although there were peaks between March/May and September/November. The mean number of snails collected was positively correlated with the water plants Nymphaea caerulea and Typha species. Overall, 2.5% of B. globosus were shedding Schistosoma cercariae. In the highveld, 2.8% of B. globosus were infected with schistosome cercariae and 1.5% in the lowveld, with the figures at individual sites ranging from 0-18.8% in the highveld and from 0-4.5% in the lowveld. The cercariae recorded here were a mixture of S. mattheei and S. haematobium since they share the same intermediate host. The transmission of Schistosoma cercariae exhibited a marked seasonal pattern, being more intensive during the hot, dry season (September/November).     

Variations in the immune response to natural Schistosoma mattheei infections in calves born to infected mothers

During previous work Schistosoma antibodies and circulating antigens were detected at birth in the serum from some calves born to Schistosoma mattheei infected mothers. The objectives of the present survey were: (1) to investigate the proportion of calves, born to cows infected with S. mattheei, which have specific antibodies and circulating schistosome antigens present in their serum at birth and (2) to investigate whether the presence or absence of these specific antibodies and/or circulating antigens at birth may affect the pattern of a natural S. mattheei infection in calves from 4 to 5 months of age, when the colostral antibodies are thought to be of negligible importance. A total of 28 calves born to infected mothers were randomly selected. Faeces, serum and colostrum samples were collected from the cows at calving, serum samples were collected from the calves at birth (day 0), after intake of colostrum (day 1) and monthly thereafter up to the age of 10 months. Both serum and colostrum samples were analysed for IgG(H+L) against SWAP mattheei and schistosome circulating anodic antigen (CAA) levels. The calves were exposed to a natural challenge from the age of 4-5 months. Faecal samples were collected from the calves monthly, starting at an age of 5 months up to 10 months, and were examined for faecal egg counts. Nine (group 1) out of the 28 calves were found to have specific antibodies in their serum at birth, in 5 of them CAA levels were also detected. In the other 19 calves (group 2) no IgG(H+L) or CAA were detected. At the end of the study faecal egg counts and CAA levels were significantly lower in calves from group 1 compared to group 2. Results confirm earlier work that specific antibodies and circulating antigens may be present in serum from calves at birth, and show that these calves have lower faecal egg counts and CAA levels after exposure to a natural challenge.     

Description and classification of abnormal cercariae of Schistosoma mattheei and a method of concentration and collection

Over a period of about 12 years, 30 abnormal Schistosoma mattheei cercariae were found among a total of approximately 2.8 million examined. Initially seven were recovered from about 1.02 million (0.0007%), which were examined individually while being counted with the aid of a stereoscopic microscope. Subsequently, on the strength of relatively high percentages of abnormal individuals recovered when counting cercariae that failed to penetrate into oxen, it appeared that the morphologically abnormal cercariae were unable to swim and would mostly sediment out of a suspension while most of the normal cercariae would remain swimming. This surmise is supported by recovery of 23 morphologically abnormal cercariae (0.001%) from about 1.8 million, by examining the sediment after the cercarial suspension had been left standing undisturbed in glass measuring cylinders. The abnormalities ranged from aberrant tails only (e.g. an underdeveloped tail, or different degrees of schism) or aberrant heads only, to abnormalities of both the heads and tails. A suggested schematic classification of abnormal cercariae is presented. A young, adult hamster was exposed to eight S. mattheei cercariae with complete schism of the shaft of the tail, by pipetting the cercariae onto the shaved abdominal skin of the anaesthetised animal. Two underdeveloped females were subsequently encountered in squash preparations of the liver when the hamster was killed for worm recovery 10 weeks after infection, thus showing that some of the abnormal cercariae were viable. A method is also described for killing and fixing cercariae while retaining some of the shining brilliance of live cercariae, without them becoming shrivelled, granular and semi-opaque, as occurs when cercariae die spontaneously or are killed with heat. This is apparently the first report of abnormal cercariae of S. mattheei. In addition, a method of concentrating abnormal cercariae after emergence from a snail, a schematic classification of abnormal cercariae and a method for killing and fixing cercariae while retaining much of the shiny brilliance of live cercariae are also reported for the first time as far as is known.