Macracanthorhynchus Hirudinaceus Research Articles

Helminths of Wild Boar in Spain

Forty-seven wild boars (Sus scrofa) collected from two areas in the province of Valencia (eastern Spain) were examined for digestive and respiratory helminth parasites. Helminth species and their prevalence were Taenia hydatigena cysticercus (19%), Ascarops strongylina (87%), Physocephalus sexalatus (6%), Ascaris suum (2%), Metastrongylus spp. (85%), Capillaria sp. (2%) and Macracanthorhynchus hirudinaceus (21%). Trichinella spp. were not found. Physocephalus sexalatus, A. suum, Capillaria sp. and M. hirudinaceus were found only in wild boars collected from one area (National Hunting Reserve of Cortes de Pallás). Macracanthorhynchus hirudinaceus did not occur in hogs < 1-yr-old, whereas the intensity of Metastrongylus spp. infection was the greatest in this age group.

Element concentrations in the archiacanthocephalan Macracanthorhynchus hirudinaceus compared with those in the porcine definitive host from a slaughterhouse in La Paz, Bolivia

Concentrations of lead and cadmium, determined by electrothermal atomic absorption spectrometry, and concentrations of the elements barium, cadmium, copper, iron, magnesium, manganese, nickel, lead, selenium and strontium, determined by inductively coupled plasma mass spectrometry, in the acanthocephalan Macracanthorhynchus hirudinaceus and its porcine final host, sampled at a slaughterhouse in La Paz, Bolivia, were compared. Inductively coupled plasma mass spectrometry analysis revealed that most of the elements were found at higher concentrations in the acanthocephalan than in different tissues of its host. The bioconcentration of elements in M. hirudinaceus compared with the host intestine, listed in order of decreasing values, was as follows: Cd > Pb > Ni > Sr = Cu > Mg > Se > Fe = Mn = Ba. Analysis by electrothermal atomic absorption spectrometry showed that M. hirudinaceus contained 85, 85, 56 and 24 times higher lead levels compared with hosts muscle, liver, kidney and intestine, respectively. The mean cadmium concentration of the parasite was 32 times higher than that of the liver and five times higher compared with porcine kidney. The metal distribution within the body of M. hirudinaceus was as follows: cement gland > testes > lemnisci > eggs = tegument for lead and lemnisci > testes > cement gland > tegument > eggs for cadmium. Therefore, the hypothesis that parasites excrete toxic metals with the shells of their eggs seems not to be valid for M. hirudinaceus. It is concluded, that not only eoacanthocephalans and palaeacanthocephalans parasitising fish, but also archiacanthocephalans from mammalian hosts, are able to bioaccumulate metals.

Endectocidal efficacies of doramectin in naturally parasitized pigs

The studies reported here were conducted to investigate the effectiveness of doramectin, given intramuscularly at the rate of 300 μg kg −1 of bodyweight, in the treatment of naturally acquired porcine nematodosis and acariasis. Twenty pigs demonstrated to be naturally infected with pulmonary and gastrointestinal nematodes were used in one control study, and 22 pigs demonstrated to be naturally parasitized with Sarcoptes scabiei var. suis were used in a second study. In both studies, animals were evenly divided between doramectin plus vehicle and vehicle-treated groups by restricted randomization. In the anthelmintic study, all pigs were necropsied for parasite collection on post-treatment Days 14 and 15. The acaricidal evaluation study was 28 days in duration after treatment, with mite population quantifications on the day of treatment and on post-treatment Days 7, 14, 21 and 28. Doramectin proved 100% effective in the removal of Metastrongylus salmi, M. elongatus, M. pudendotectus, Strongyloides ransomi, Ascaris suum and Oesophagostomum dentatum. Levels of Hyostrongylus rubidus, Ascarops strongylina and Macracanthorhynchus hirudinaceus, as observed at necropsy in the doramectin-treated pigs, were reduced by 99.2%, 99.5% and 62.1%, respectively, as compared with levels seen in the control pigs. In regard to Sarcoptes scabiei var. suis, no live mites were recovered from doramectin-treated pigs during the 7–28 day post-treatment period. In conclusion, doramectin proved highly effective in the treatment of naturally acquired porcine nematodosis and Sarcoptes scabiei var. suis infestation. In addition, all treatments were safe and well tolerated, with no adverse reactions noted in any trial animals.

Study on a new egg count technique for Macracanthorhynchus hirudinaceus and Ascaris suum

This paper deals with a new egg count technique for Macracanthorhynchus hirudinaceus and Ascaris suum. The making of the new counter and the operation are described. The eggs of M. hirudinaceus in the upper, the middle and the lower levels of the sediment from swine feces were counted by the new egg count technique and the numbers of the eggs in the sedimentary liquids diluted two, four, six, eight and ten times were nearly similar. This indicates that the eggs dispersed evenly in the sediment and that the new technique is reliable. Comparison between the new technique and the McMaster technique shows that the number of the eggs counted by the new technique is more than that by the McMaster technique. The result show that the new technique has advantages because it requires only simple tools, water for flotation and a shorter time of operation.

Persistence of a Recurrent Group of Intestinal Helminth Species in a Coyote Population from Southern Texas

The persistence and interrelationships of a recurrent group of intestinal helminth species in a coyote population from southern Texas were determined; data were collected at 4-yr intervals (1979, 1983, and 1987). The a priori expectation was that a defined recurrent group of helminth species persisted over time and that the respective helminth species were stable in terms of their abundances. The Fager index and subsequent recurrent group analysis indicated a small group of taxonomically unrelated recurring species of helminths that always demonstrated affinities with each other and occasionally with certain of the remaining species. Although there were differences across host subpopulations delineated by sex and age, temporal changes reflective of extrinsic environmental variables acting on certain helminth species appeared to have the greatest effect on recurrent group size and structure. Three of the 8 common intestinal helminth species (Ancylostoma caninum, Oncicola canis, and Alaria marcianae) occurred in all recurrent groups. Thus, there was temporal persistence of a small recurrent group of dominant helminth species that formed the basis of the intestinal helminth community in this coyote population.

Ultrastructure of the spermatid and spermatozoon of Macracanthorhynchus hirudinaceus.

The ultrastructure of the spermatid and spermatozoon of Macracanthorhynchus hirudinaceus (Archiacanthocephala) was studied by means of transmission electron microscopy. The flagellum and nucleus in the spermatid gradually expanded simultaneously. The karyoplasma of the spermatid transformed into dense inclusions and a multibarrel structure, which were also found in the spermatozoan body. The multibarrel structure was located close to the flagellum and consisted of many irregular microtubes. The flagellum of the developing spermatozoon was observed in a concavity of the spermatid nucleus. The microtubule arrangement of the flagellum was "9 + 2". No mitochondria or acrosome were observed in spermatozoa.

Ultrastructural Study of the Defense Reaction against the Larvae of Macracanthorhynchus hirudinaceus in Laboratory-Infected Beetles

Tenebrionid beetles (Zophobas morio) from Peru were experimentally infected with eggs of Macracanthorhynchus hirudinaceus from China. A de- fense reaction of the beetles against the acanthella and cystacanth of the parasite was observed by means of transmission electron microscopy. Beginning at 1 wk postinfection, many hemocytes of the infected beetles were found adhering to the outer surface of the enve- lope that encloses the acanthella. Some of the host's hemocytes penetrated the envelope and attached to the tegument of the acanthella and cystacanth, so that the outer membrane of the larval tegument was damaged. Starting at 50 days postinfection some of the cysta- canths were seen to disintegrate.

Efficacy of an in-feed preparation of ivermectin against endoparasites and scabies mites in swine

Summary In 2 trials, the efficacy of an in-feed preparation of ivermectin was evaluated in 40 pigs naturally infected with endoparasites and Sarcoptes scabiei var suis. Treated pigs (n = 10 in each trial) were fed a ration containing 2 ppm ivermectin for 7 days, followed by consumption of a nonmedicated ration for the remainder of the trial. Control pigs (n = 10 in each trial) were fed a complete, nonmedicated ration for the duration of the trial. Pigs in trial A were monitored for 14 days after treatment; those in trial B were monitored for 35 days after treatment. In trial A, treatment efficacy of ivermectin was 100% against Ascaris suum, Physocephalus sexalatus, Oesophagostomum dentatum, O brevicaudum, Metastrongylus spp; 99.8% against Ascarops strongylina; 90.9% against Trichuris suis; and 13.1% against Macracanthorhynchus hirudinaceus. At the terminus of the trial, statistically significant (P &lt; 0.05) differences were observed between numbers of treated and control pigs infected with A suum, Ascarops strongylina, and Oesophagostomum spp. On posttreatment day 14, S scabiei were not found in any scrapings taken from treated pigs, but were found in scrapings from 3 of 10 control pigs. The number of infested pigs in the treatment group was not statistically different from the number of infested pigs in the control group. In trial B, treatment efficacy was 100% for A suum and Metastrongylus spp; 96.9% for Ascarops strongylina; and 76.9% for M hirudinaceus. At the terminus of the trial, statistically significant (P &lt; 0.05) differences were evident between numbers of treated and control pigs infected with A suum, Ascarops strongylina, and Metastrongylus spp. On posttreatment days 7, 21, and 35, S scabiei were not found in scrapings taken from treated pigs. On posttreatment days 7, 21, and 35, S scabiei were found in scrapings from 8, 6, and 1 pig, respectively, whereas live mites were not found on scrapings taken from treated pigs on these days. Statistically significant (P &lt; 0.05) differences were evident between the numbers of infested pigs in the treated and control groups on days 7 and 21. Ivermectin fed to swine ad libitum in a complete ration at 2 ppm was shown to be highly effective as an anthelmintic and acaricide.

Helminth Parasites of the Raccoon (Procyon lotor) from North-Central Arkansas

Twenty-three species of helminths (4 trematodes, 2 cestodes, 14 nematodes, and 3 acanthocephalans) were found in the gastrointestinal tract, lungs, pancreas, tongue, urinary bladder, and subcutaneous tissues of 30 live-trapped or hunter-shot raccoons from north-central Arkansas between November 1989 and April 1990. Helminths were not detected in the brain, diaphragm, gallbladder, heart, liver, reproductive system, or trachea. Each raccoon examined was infected with 3 or more of the following helminths: Brachylaima virginiana, Eurytrema procyonis, Fibricola cratera, Pharyngostomoides procyonis, Atriotaenia procyonis, Mesocestoides spp., Arthrocephalus lotoris, Capillaria aerophila, Capillaria plica, Capillaria procyonis, Capillaria putorii, Crenosoma goblei, Cruzia americana, Dirofilaria tenuis, Dracunculus insignis, Enterobius sp., Gnathostoma procyonis, Molineus barbatus, Physaloptera rara, Trichinella spiralis, Centrorhynchus wardae, Macracanthorhynchus ingens, and Oligacanthorhynchus tortuosa. All helminths collected with the exception of D. insignis constitute new geographic distribution records. Occurrences of C. aerophila, C. wardae, and O. tortuosa are new host records. One nymphal pentastome, Porocephalus crotali, was found in the liver of 1 raccoon, constituting a new host record.

Comparative investigations of the morphology and chemical composition of the eggshells of Acanthocephala

Eggshells of Macracanthorhynchus hirudinaceus (Archiacanthocephala) were investigated for their fine structure as well as their chemical composition. The acanthor larvae are surrounded by four eggshells (E1-4) separated by interstices of low electron density (G1-4). As these envelopes are secreted in different sequences and are reinforced to different degrees, their appearance varies throughout development. The outermost eggshell (E1) of this species has a tripartite appearance; it contains neither chitin nor keratin. Keratin appears in E2 and E3. It was localized electron microscopically using anti-keratin and, for the first time by fluorescence microscopy with the bromobimane reaction. Keratin occurs in two forms: in the second envelope (E2) it consists of twisted struts of filaments, whereas in the innermost sublayer of the third envelope (E3) it shows a conspicuous cross-striation; in the first and second sublayers of E3, neither keratin nor a discernible structure is present. Chitin occurs in the innermost layer (E4). The interstices G1, G3 and G4 seem to contain glycoproteins, whereas interstice G3 seems to contain some type of carbohydrate. After the extraction of proteins including keratin with sodium dodecyl sulfate (SDS) and dithiothreitol (DTE) only layers E1 and E4 remained.

Fine Structure of Anterior Terminus of Apical Sense Organ in Macracanthorhynchus hirudinaceus (Acanthocephala)

The apex of the proboscis of Macracanthorhynchus hirudinaceus is crowned by a cone-shaped projection with a small opening in its center. The bottom of this opening is the anterior terminus of the apical sensory organ. When viewed in transverse section, the anterior terminus of this organ appears as a series of distinct layers that encircle a central cone enclosing a complex arrangement of nerves and a sensory support cell duct. Four membrane-defined layers encircle the cone area. The outermost glycocalyx is morphologically identical with that described on the metasoma. The second layer, or tegument, is similar in appearance to that observed on the trunk except for the greater abundance of keratinlike bundles throughout. These bundles are also organized into a loose network along the inner tegumental membrane. The third layer, a latticework of fine filaments containing few organelles, has an erratic boundary that occasionally extends into layer 4. The area adjacent to the inner and outer boundary contains numerous vesicles. Layer 4 has 2 distinct zones. The outer contains filaments arranged as in circular muscle; whereas, the medial lacks such filaments but consists of a finely grained matrix. Radiating throughout both zones are numerous osmiophilic bundles of fibers. The cone at this level contains 8 branches of the apical sensory nerves that interdigitate with the duct from the sensory support cell. Numerous filaments and vesicles are associated with this complex.

Helminths of the Raccoon (Procyon lotor) in Western Kentucky

Seventy raccoons (Procyon lotor) from western Kentucky were examined for helminths from December 1985 through May 1986. Twenty-three species of helminths were collected including 10 species of Trematoda (Brachylaima virginiana, Euryhelmis squamula, Eurytrema procyonis, Fibricola cratera, Gyrosoma singulare, Maritreminoides nettae, Mesostephanus appendiculatoides, Metagonimoides oregonensis, Paragonimus kellicotti, Pharyngostomoides procyonis), 2 species of Cestoda (Atriotaenia procyonis, Mesocestoides variabilis), 10 species of Nematoda (Arthrocephalus lotoris, Baylisascaris procyonis, Capillaria putorii, C. plica, Crenosoma goblei, Dracunculus insignis, Gnathostoma procyonis, Molineus barbatus, Physaloptera rara, Trichinella spiralis), and 1 species of Acanthocephala (Macracanthorhynchus ingens). A mean of 6.4 (3-11) helminth species per host was recorded. Fibricola cratera, Atriotaenia procyonis, Mesocestoides variabilis, Arthrocephalus lotoris, Capillaria plica, Dracunculus insignis, Molineus barbatus, and Physaloptera rara were ubiquitous parasites of the raccoon, whereas specific nidi were observed for Eurytrema procyonis, Gyrosoma singulare, Paragonimus kellicotti, Baylisascaris procyonis, Trichinella spiralis, and Macracanthorhyncus ingens. With an overall prevalence of 10% or higher, 15 of the 23 helminth species were considered common parasites of the raccoon in western Kentucky. When the 10% prevalence rate was applied within geographical quadrants to correct for the presence of nidi it was found that 18 of the 23 helminth species were common and 5 were regarded as rare parasites of the raccoon. Two species of nematodes, T. spiralis and B. procyonis, displayed a markedly higher prevalence in male raccoons.

Survival of Macracanthorhynchus Ingens in Swine and Histopathology of Infection in Swine and Raccoons

Animal husbandry aimed at preventing Macracanthorhynchus hirudinaceus infections in swine is not successful in preventing exposure to Macracanthorhynchus ingens, and it is probable that pigs occasionally acquire acanthocephalans of that species. In some pigs, M. ingens survived 2 weeks and grew several millimeters. In such cases, destruction of villi, erosion of epithelium, leukocytic infiltration, and altered cytological structure at attachment sites accompanied the infection. Penetration was limited to the submucosa, and the effects were not as severe as those occurring in the presence of M. hirudinaceus, which enters the muscularis.

Helminth Parasites of the Raccoon (Procyon lotor) from Tennessee and Kentucky

From December 1980 through November 1981, 145 raccoons (Procyon lotor) from Land Between The Lakes in Stewart County, Tennessee, and Lyon and Trigg counties, Kentucky, were examined for helminth parasites. Diaphragms were examined for Trichinella spiralis and gastrointestinal tracts for other helminth parasites. Ten species were found including 7 nematodes (T. spiralis, Physaloptera rara, Arthrocephalus lotoris, Molineus barbatus, Baylisascaris procyonis, Gnathostoma procyonis, Dracunculus insignis), 2 cestodes (Mesocestoides variabilis, Atriotaenia procyonis), and 1 acanthocephalan (Macracanthorhynchus ingens). Dracunculus insignis is reported from Tennessee and Kentucky raccoons for the first time. Of the parasites detected, only T. spiralis showed a statistically significant preference for one sex (male) over the other. It was also the only parasite found in greater prevalence in relation to age classes (highest in age classes III and IV). Arthrocephalus lotoris, M. barbatus, B. procyonis, M. ingens, and D. insignis all had seasonal trends in prevalence, and winter intensity of parasites was found to be most similar to that of spring, spring to summer, and summer to fall. The raccoon, Procyon lotor, is a medium-sized mammal that is widely distributed in North America (Hall, 1981). Due to its economic importance, it has been the subject of numerous biologic investigations (see Lotze and Anderson, 1979). Of the previous studies, many have been directed toward questions relating to raccoon parasites (e.g., Chandler, 1942; McNeil and Krogsdale, 1953; Babero and Shepperson, 1958; Jordan and Hayes, 1959; Harkema and Miller, 1964; Bafundo et al., 1980). However, with the exception of Bafundo et al. (1980), little attention has been given to raccoon parasites in Tennessee. Bafundo et al. (1980) investigated prevalence and intensity of helminth parasites in the digestive tract and examined interlocality variation in P. lotor using helminth parasites as characters. This work provided information relating to broad trends in variation of a selected group of endoparasites that were collected during a restricted time period (as is the case in most previous studies). They grouped raccoons occurring in large physiographic regions as single samples and primarily utilized P. lotor specimens taken during October through February (the hunting season). To date, few investigators (see Lotze and Anderson, 1979) have examined raccoon parasitism in a small geographic area over extended periods. Studies of this type appear critical in order to provide a complete understanding of the natural Received 12 December 1983; revised 26 February 1985; accepted 26 February 1985. history of P. lotor and raccoon (host)-parasite relationships. The purpose of the present investigation was to study the helminth parasites of P. lotor (in a small geographic area) as follows: (1) determine the prevalence; (2) compare prevalence between male and female raccoons; (3) examine prevalence in relation to age of the host; (4) observe seasonal trends in prevalence and intensity of parasite species; (5) examine interspecific associations of prevalence. MATERIALS AND METHODS The study area (Land Between The Lakes = LBL) was a 69,000 ha peninsula located between Kentucky Lake and Lake Barkley in Stewart County, Tennessee, and Lyon and Trigg counties, Kentucky. With cooperation of the Tennessee Valley Authority (TVA), 145 P. lotor were collected from December 1980 through November 1981. Counties from which raccoons were collected and sample sizes for male (given first) and female P. lotor are as follows: Tennessee, Stewart-23, 15; Kentucky, Lyon-11, 16; Trigg-35, 38. Specific locality information was not available for 3 additional males and 4 females. Specimens were taken during different seasons (those of the calendar year) in the following numbers (male sample size is given first): winter-8, 13; spring-20, 15; summer-27, 25; fall17, 18. Seasonal data were incomplete for 2 females. Most animals were collected by gun with the use of dogs or spotlight from a boat or truck. Animals were frozen and housed in TVA facilities and later transported to the Department of Biology, Memphis State University, where they were examined. Sixty-one specimens (those with available skeletal material) were aged as juvenile (class I, n = 12), subadult (class II, n = 8), adult (class III, n = 15), or old adult (class IV, n = 26) following Junge and Hoffmeister (1980). Sex of all specimens was recorded. In-

Protonephridia in Male Macracanthorhynchus hirudinaceus (Acanthocephala): An SEM Study

The protonephridium and associated excretory bladder of male Macracanthorhynchus hirudinaceus was examined by scanning electron microscopy. These excretory organs were located on the dorsal surface at the junction of the dorsal ligament sac and genital sheath. The protonephridium contained between 275 and 315 flame bulbs in each mass. The pattern formed by these flame bulbs was shown as well as their relative position to surrounding structures. The flame bulbs did not appear to wave or move around when viewed in living worms. The excretory bladder was very pleomorphic; when full, it was round or barrel-shaped, but when partially filled it may have fingerlike extensions from its posterior terminus. Several SEM photographs are presented which show a few of the different patterns observed in the excretory bladder. The posterior terminus of the bladder was unattached to the genital sheath.

Population Dynamics across Selected Habitat Variables of the Helminth Community in Coyotes, Canis latrans, from South Texas

The effects of selected intrinsic variables operating on host subpopulations and of extrinsic variables across the collective host population on the distributions of 10 common helminth species from coyotes in south Texas were compared. The intrinsic variables of host sex and presence and severity of sarcoptic mange had little effect on the distributions of most helminth species. The combined influences of (1) seasonal changes across the collective host population and (2) host subpopulations delineated by age were responsible for the overdispersed distributions of Oncicola canis, Physaloptera rara, and Protospirura numidica. Overdispersion in Ancylostoma caninum, Alaria marcianae, and Spirocerca lupi populations resulted almost exclusively from the heterogeneity of factors contributing to their rates of establishment, survival, and reproduction as generated across host age subpopulations. Aggregated abundances of A. caninum and A. marcianae occurred in young hosts, but were cumulative in older animals infected with S. lupi. The hypothesis that heterogeneity within the host population, rather than across the collective host population, is the main factor generating overdispersion in natural populations was confirmed for only 3 of 10 helminth species (A. caninum, A. marcianae, and S. lupi). The effects of extrinsic factors operating across the collective host population appeared to be equal to, or in some instances of greater importance than, these forces operating over host subpopulations in determining the dispersion patterns of some helminth species (O. canis, P. rara, and P. numidica). The distributions of Taenia pisiformis, Mesocestoides lineatus, Oslerus osleri, and Toxascaris leonina were not affected, or only minimally influenced, by these intrinsic or extrinsic variables. The effects of these habitat variables on dispersion patterns are highly correlated with the life cycle and mode of transmission of the respective helminth species.

Apical Sense Organ of Macracanthorhynchus hirudinaceus (Acanthocephala)

The apical sense organ in Macracanthorhynchus hirudinaceus consists of a broadly pestle-shaped, binucleate apical cell and associated structures that include processes from the apical sensory nerves and the sensory support cell duct, formerly named the anterior medial nerve. That duct and two nerve fibers of the apical sensory nerves enter the apical cell near the posterior end and extend anteriorly through the core to terminate in a depression at the apex of the proboscis. Each of the anterior proboscis nerves divides just posterior to the apical cell, forming branches that extend anteriorly on the outer surface of this cell. Additional divisions of these fibers occur near the crown. A diagram of the sensory support cell shows its general features and relationship to the apical and lateral sense organs. Receptor morphology has been only superfi- cially understood in Acanthocephala. Although both sexes of all species are thought to have pos- terior receptors associated with copulation, an- terior receptors are not uniformly present on the proboscis. Harada (1931) described only lateral sense organs in Oligacanthorhynchus micro- cephala (= Hamanniella microcephala). Jilek and Crites (1979) reported that Gracilisentis graci- lisentis had neither an apical or lateral sense or- gan on its proboscis. We report here our obser- vations on morphology of the apical sense organ in Macracanthorhynchus hirudinaceus. Our use

A Support Cell to the Apical and Lateral Sensory Organs in Macracanthorhynchus hirudinaceus (Acanthocephala)

A large multinucleate cell is described with extensions that serve the apical and lateral sensory organ in Macracanthorhynchus hirudinaceus. This cell is located ventral and slightly anterior to the cerebral ganglion. The body of the cell rests on the ventral surface of the midventral longitudinal receptacle (MVLR) muscle. Four large processes, one from each corner, exit this cell. The two posterior processes follow the ventral receptacle muscles as they penetrate the proboscis sheath. Once inside this sheath they turn anteriorly, fuse, and then continue as a single process to the apical sensory organ. Each of the two anterior processes extends to opposite lateral surfaces of the MVLR muscle as they proceed anteriorly. Each anterior process then extends a short distance laterally between the proboscis sheath and longitudinal receptacle muscle. They then turn anteriorly accompanied by a large number of neurites. Eventually each extends through the body wall and terminates in a lateral sensory organ. A study of sensory organs located on the pro- boscis of Macracanthorhynchus hirudinaceus led to the discovery that all structures connecting to these external receptors were not nerves. Ques- tions were raised regarding previous identifica- tions when it was discovered that the nerve iden- tified as anterior medial nerve (Kaiser, 1893; Rauther, 1930; Kilian, 1932) did not enter the cerebral ganglion. We also perpetuated this error beginning in 1970 when we first published on the nervous system of M. hirudinaceus. We used the same terminology as previous authors and traced this large ductlike process from the posterior margin of the apical sensory organ to the ventral surface of the cerebral ganglion where the process divides. We incorrectly assumed that when these processes disappeared they did so because they had entered the cerebral ganglion. Thinner sec- tions and better preparations have now shown that this structure, previously identified as the

Intestinal Lysophospholipase and Eosinophil Responses to Macracanthorhynchus hirudinaceus (Acanthocephala)

Lysophospholipase (EC 3.1.1.5) has been shown to be elevated during rodent infection with Hymenolepis nana (Ottolenghi, 1973, Lipids 8: 426-428), Nippostrongylus brasiliensis (Ottolenghi et al., 1975, Exp. Parasitol. 38: 96-104), Trichinella spiralis (Larsh et al., 1974, Exp. Parasitol. 36: 299-306), Angiostrongylus cantonensis (Ottolenghi et al., 1977, Inf. Imm. 15: 13-18), and with Mycoplasma pulmonis (Laubach et al., 1978, Inf. Imm. 22: 295-297). The increased enzyme activity was associated with an increased eosinophil response (Ottolenghi, 1970, Lipids 5: 531-538) and was directly affected by the T-lymphocyte response (Goven and Moore, 1980, Z. Parasitenkd. 61: 265-269). Lysophospholipase levels were shown to be acquired faster and at higher plateau levels after reinfection (Larsh et al., 1975, Exp. Parasitol. 37: 233238) but increased worm burdens were not found to result in lysophospholipase activity above a plateau level (Laubach et al., 1978, J. Parasitol. 64: 1145-1146). Goven and DeBuysscher (1979, Am. J. Vet. Res. 40: 1469-1471) demonstrated that T. spiralis infection of swine results in increased lysophospholipase activity in the small intestine accompanied by an increased number of peripheral eosinophils. Experimental results showed that the lysophosopholipase response in swine is similar to that in rodents. The present study was thus designed to determine if the lysophospholipase response of swine also occurs during infection with Macracanthorhynchus hirudinaceus. Several dozen infected male pigs were obtained from the local abbatoir and their intestinal tracts were examined for M. hirudinaceus. Female worms were collected and their body lengths (mm) were recorded. Few male worms were found and subsequently were not used in the experiment. The female worms were grouped into categories of 100, 150, 200, 250, and 300 mm body lengths. Eight worms were collected in each group. All worms were collected from the middle one-third of the small intestine of each pig. The lesion at the attachment site of each of the worms and tissue samples 7 to 8 cm away from each lesion (control tissue samples) were assayed for lysophospholipase activity (Ottolenghi, 1973, Lipids 8: 426-428). Intestinal tissue was minced with a scissors, homogenized, and immediately assayed for lysophospholipase by mixing with lysolecithin and incubating at 37 C for 30 min. Enzymatic reactions were stopped using sulfuric acid, isopropyl alcohol and water. Liberated, free fatty acids were extracted with heptane and quantitated by titrating the heptane solutions with sodium hydroxide and bromothymol blue solution. Lysophospholipase activity was measured as micromoles activity/g intestinal tissue/hr. A portion of each intestinal lesion and control tissue samples were also fixed in 10 percent buffered formalin. Tissues were stained with hematoxylin-eosin, embedded in paraffin, sectioned and mounted onto slides. Tissue sections were examined for cell types at x 1,000 using brightfield illumination. A significant increase in eosinophils was determined to be more than three eosinophils per field. Lysophospholipase activity and intestinal tissue eosinophilia of lesions were statistically compared to control tissues using the grouped Student's t-test (Snedecor and Cochran, 1972. Statistical methods). Values greater than 0.05 were regarded as not significant. The lysophospholipase activity of the infected intestinal tissue was found to be highest in the lesions from the smaller worms measuring 100 mm in length (Fig. 1). Eosinophil numbers in the lesions from the smaller worms were also increased (range from 6.3 to

Anatomy of the Cerebral Ganglion in Oligacanthorhynchus tortuosa (Acanthocephala) from the Opossum (Didelphis virginiana)

The anatomy of the cerebral ganglion from Oligacanthorhynchus tortuosa (Acanthocephala) resembles that previously described for large acanthocepalans from mammals. The cell population was equally distributed between each half of the ganglion, there were 38 cells on each side with seven cells centrally located. The core of the ganglion or neuropile occupied the central part of the ganglion and was the site for the crossover for many cell processes. Many of the axons from these cells exited from the side opposite the soma. The cell bodies predominated on the ventral surface while the dorsal surface was more of a mixture of cell bodies and neurites. The cytoarchitecture of these cells varied considerably but most had a large round nucleus with well-defined nucleoli. There were 83 cells, two of which were binucleate. The two binucleate cells were located at opposite extremes of the anteroposterior axis of the ganglion. The anterior binucleate cell was adjacent to the dorsal surface whereas the posterior cell was central and near the posterior terminal of the ganglion.