A retrospective analysis of hospital records in 3 ecological zones of Nigeria was carried out to ascertain the prevalence of human taeniasis, cysticercosis and hydatidosis.

The prevalence of Taenia infection in Sudan, Bauchi Plateau and Northern Guinea zones wa 0.9%, 0.6% and 0.6% respectively. The prevalence of human taeniasis by age and sex in the 3 ecological zones indicates that males were more often infected. Because males by habit eat more “suya” (half-grilled beef) than females, they are more likely to be exposed to Taenia saginata cysts. As for age factor, Taenia infection was more common up to the age of 40.

Human hydatidosis was recorded only once in the Sudan zone and was not recorded at all in the Northern Guinea and Bauchi zones. Human cysticercosis was not documented in any of the three ecological zones covered by the survey.

It is suspected that the low prevalence or the non-documentation of some of these diseases is due to poor diagnostic facilitis and inefficient disease-recording system.

Ascaridoid nematodes reported from terrestrial and freshwater chelonians are described under two monotypic genera, Angusticaecum and a new genus Krefftascaris respectively. The former genus contain A. holopterum (Rodolphi, 1819) Baylis, 1920 [synonym A. brevispiculum Chapin, 1924], reported in the natural state from testudinid and emydid tortoises in Europe, U.S.S.R., Iran, Brazil and North Africa. Teh latter genus contains a new species, K. parmenteri, reported from chelid freshwater turtles in Eastern Australia. It is concluded that the former is most closely related to species in other genera in terrestrial reptiles, whereas the latter is closest to Gedoelstascaris spp. in crocodilians. Host-parasite relationships over evolutionary time between ascaridoids and chelonians are discussed.

Dauerlarvae of Pelodera strongyloides, recovered from two species of lemmings, Dicrostonyx groenlandicus (Traill) and Lemmus trimucronatus (Richardson) trapped at Eskimo Point, N. W. T., were cultured on agar medium with E. coli. Development from egg to adult stage was followed. Eggs hatched between 22 and 26 hours at 22°C. The first moult occurred 24 to 28 hours after the eggs hatched, the second at 40 to 48 hours, the third at 60 to 64 hours and the fourth at 84 to 88 hours at 22°C. Adults lived approximately 5 to 6 days and females oviposited for 2 to 3 days during this time. All stages were measured and described. The effect of temperature on development was examined. Dauerlarvae survived freezing temperatures, short periods of desiccation and prolonged periods without food.

Nonspecific esterase (NSE), acetylcholinesterase (AChE) and pseudocholinesterase (ChE) have been localized by histochemical methods in various tissues of a cestode, Raillietina (Raillietina) johri obtained from the intestine of pigeon.

NSE has been found in the rostellum, suckers, hooks, tegument, subtegumental muscle, excretory canal, cirrus sac, vagina and eggs. Two types of cells have been recognized on the scolex surface—some are NSE positive and others are NSE negative. AChE, besides being localized in nerves, has also been visualized in almost all the structures as in case of NSE except in hooks, excretory canal and eggs. Additionally AChE has been observed in the vas deferens and sperm ductules. ChE has been observed only in nerves, vas deferens, cirrus sac and vagina; the intensity of enzyme activity being low when compared with AChE. Possible involvement of these enzymes in the physiology of the parasite has been discussed.

The indirect fluorescent antibody technique has been applied to detect antibody levels in jirds (meriones unguiculatus) infected with Brugia malayi. Sonicated antigens were prepared from microfilariae and adult worms. Sonicated microfilariae were found to be satisfactory for this purpose. Cyanogen bromide-activated sepharose coated with soluble antigens prepared from microfilariae and adult worms was also used to detect antibodies to Brugia infections. The present observation show that these techniques can be usefully applied for detection of filarial infections. Antibody titres in infected jirds generally ranged from 1: 16 –1:256 and were not affected by treatment with diethylcarbamazine.

A retrospective analysis of slaughterhouse records during the pre-veterinary-organized meat inspection era (before 1970) for cysticercosis and hydatidosis in food animals showed that parasitic cysts were documented but not identified and that the numbers of slaughtered animal species harbouring various parasitic cysts were not recorded. Since the various parasites which the meat inspectors observed were not identified, the prevalence of species encountered could not be determined.

An analysis of abattoir records during the veterinary meat inspection era showed that Cysticercus bovis and C. cellulosae infections were documented in cattle and pigs respectively. Moreover, hydatid cysts were detected in cattle, pigs, sheep, goats and camels.

The data obtained from this survey cannot be wholly relied upon as accurate, but it can be used as a baseline for the proper evaluation of the status of these zoonotic parasitic diseases in future co-ordinated researches.

For the first 66 hours after the subcutaneous injection of rabbits with the infective larvae of Strongyloides papillosus, larvae spread gradually from the injection site to other parts of the body musculature. Their number and distribution suggests that they do so by the direct penetration of the tissues as the majority remain close to the site of injection. By 90 hours, however, the appearance of larvae in the lungs, trachea and oesophagus suggests that migration is taking place within the circulation.

Although some 90% of the total worms recovered were already established in the intestine by 8 days post-infection, significant numbers of larvae continued to be present in the muscles at 14 and 21 days. Even by 35 days the muscles of 1 of 2 rabbits still contained 43 larvae. This prolonged presence of Strongyloides papillosus in the muscle of rabbits uniformly at the early fourth stage may be analogous to the arrested development of other nematodes. While there is evidence to suggest that immunity is a major factor in the aetiology of arrested development in Strongyloides ransomi, it is an unimportant factor in the case of Strongyloides papillous in rabbits.

Antibody levels were investigated in rats infected with Breinlia booliati using the indirect immunofluorescent antibody technique. Sonicated antigens were prepared from microfilariae and adult worms. Adult worm antigen was rather unsatisfactory. The sonicated microfilarial antigen was useful in detecting antibodies in various groups of rat sera. Very high antibody levels were seen in amicrofilaraemic rats harbouring unisexual infections of varying worm loads. The singnificance of these observations are discussed.

A survey was carried out in the abattoirs in Kano (Sudan zone), Kaduna and Zaria (Northern Guinea zone) and Jos (Bauchi plateau zone) to assess the actual prevalence of bovine and porcine cysticercosis, and of hydatid cyst infections in slaughtered food animals.

Hydatid cysts were detected in all species of animals slaughtered at the abattoir in the Sudan zone where the prevalence was: camels (55.5%), cattle (14.70%), sheep (11.4%), goats (26.4%). In the Northern Guinea zone, the prevalence was: camels (50%), cattle (0%), pigs (0%), sheep (0.21%) and goats (0.79%). In the Bauchi plateau zone, sheep were found to harbour hydatid cysts, with a prevalence of 1.4%. In the various animal species, hydatid cysts were detected in the lungs, liver and spleen. Fertility rates of the hydatid cysts from various hosts were as follows: camels 94.5%, cattle 7.4%, goats 81.3%, and sheep 59.7%.

Cysticercus bovis was detected in slaughtered cattle from the three zones surveyed. Northern Guinea zone had the highest prevalence (4%), followed by Bauchi plateau zone (2.1%) and Sudan (1.9%). C. bovis was detected in the tongue, masseter muscle, heart, diaphragm and the quarters of infected cattle.

C. cellulosae was detected in 18.4% and 1.76% of slaughtered pigs examined in Northern Guinea and Bauchi plateau zones respectively. The cysts were found in the tongue, masseter muscle, heart, diaphragm, thigh and fore-limbs. No pigs were available for examination in the Sudan zone.

The data obtained in this survey are believed to be a better indication of the rate of infection in the various animal species than data obtained from previous abattoir records.

Echinococcus granulosus (Batsch, 1786; Rudolphi, 1801) infections in stray dogs were recorded in the Sudan and Northern Guinea zones at a prevalence rate of 6.2% and 1.2% respectively. The parasite was not recorded in any stray dog obtained from the Bauchi Plateau zone, although fewer dogs were examined from this zone.

The high prevalence of echinococcosis in dogs reported in the Sudan zone bears a true epidemiological relationship with the high prevalence of cystic hydatidosis recorded for slaughtered livestock within the same locality. There is therefore a strong possibility of a high rate of faecal contamination of the environments under consideration with Echinococcus eggs, which places the human population at a high risk.

Three cestode species, namely Taenia taeniaeformis Batsch, 1786, Taenia pisiformis (Bloch, 1780) and Mesocestoides litteratus (Batsch, 1786) and one nematode species, Toxocara cati Schrank, 1788, were found in wild cats collected in Grampian region, Scotland. Of the 41 cats examined, 25 were Felis silvestris, 12 were feral Felis catus and four were hybrids of F. silvestris and F. catus.

The two ascaridoids of sirenians, Heterocheilus tunicatus Diesing, 1839, and Paradujardinia halicoris (Owen, 1833), are redescribed. A basic affinity between the two species is indicated in the bilateral structure of the excretory system, the globular ventriculus, long intestinal caecum, and the form of the male tail. The subfamily Heterocheilinae is redefined so as to contain these two genera. It is proposed that the subfamily comprises a natural suprageneric group within the Ascarididae sensu Hartwich, 1974 containing, in addition to Heterocheilus and Paradujardinia, the following genera occurring in freshwater, estuarine and coastal vertebrates: Multicaecum Baylis, 1923; Dujardinascaris Baylis, 1947; Gedoelstascaris Sprent, 1978; Ortleppascaris Sprent, 1978; Brevimulticaecum Mozgovoy sensu Sprent, 1979; Krefftascaris Sprent, 1980. The suggestion is made that the ascaridoids of sirenians originated from forms in fluviatile lower vertebrates.