1. The behaviour and development of Brugia patei has been followed in the mosquito host, Mansonia uniformis, from ingestion of the microfilariae to the development of the infective stages.

2. The microfilariae penetrated very rapidly out of the stomach into the abdomen of the mosquito; 80% of them escape from the stomach during the first 50 minutes after a blood meal.

3. The microfilariae migrate from the abdomen to the thorax through fat body cells and the heart during the first 140 minutes followed engorgement and begin to penetrate the indirect flight muscles within 15 minutes from engorgement. During this migration microfilariae were found in close association, suggesting that they follow similar pathways of migration through the body of the mosquito.

4. Most microfilariae (98%) have settled in the indirect flight muscles within 2 hours of engorgement. In these muscles the larvae digest away the muscle surrounding them but do not begin to elongate until the third or fourth day after the blood meal. The rate of development varies from one mosquito host to another, but about 80% of the larvae have developed to the infective stage by the ninth to tenth days after the infective feed. The infective stages concentrate in the head and proboscis of the mosquito vector. The development of B. patei is faster than that of B. pahangi in mosquitoes from the same colony.

5. The efficiency of M. uniformis as a vector of B. patei is compared with the similar efficiency of M. longipalpis as a vector of B. malayi. In both mosquitoes the majority of the microfilariae ingested develop to the infective stage. M. uniforms is also an efficient vector of B. pahangi.

6. The development of the parasite is discussed briefly with reference to knowledge of the physiological events within the mosquito host subsequent to the blood meal.

In an attempt to demonstrate experimentally the life cycle of Fasciola gigantica, the snails Lymnaea natalensis were exposed to newly hatched miracidia of this trematode.

Angiostrongylus vasorum infection was detected for the first time in eight foxes (Dusicyon vetulus) captured in the south of the State of Minas Gerais, Brazil. Two crossbred dogs were successfully infected orally with larvae from the foxes' faeces.

A modification of gDNA extraction was developed for the polymerase chain reaction (PCR) technique, intended for the detection and differentiation of Toxocara spp. eggs in soil or sediments. Sand samples from sandpits confirmed as being contaminated with Toxocara spp. eggs by the flotation technique were analysed by PCR. The use of proteinase K made it possible to obtain genomic DNA from the sample without needing to isolate eggs using flotation or to inactivate PCR inhibitors present in the sand. Specific primers in the PCR reaction allowed discrimination between T. canis and T. cati eggs. The modification simplified the procedure, thanks to eliminating the step of gDNA isolation from eggs, which is both laborious and difficult.

Counterimmunoelectrophoresis revealed the presence of precipitin antibody in all of 6 dogs and the 1 cat infected with Dirofilaria immitis and in the serum of 17 of 24 individuals living in a setting of hyperendemic subperiodic bancroftian filariasis. Antigens used in the test were prepared from microfilariae and adult male D. immitis. Some humans and animals had antibodies to both antigens while others had antibodies against microfilariae or adult worms only. The presence of soluble circulating antigen was detected in the sera of two dogs with high microfilaraemias.

Following oral administration to sheep, chlamydospores of a Mexican isolate of Duddingtonia flagrans (FTHO-8) survived passage through the digestive tract and subsequently grew on corn meal agar plates. The fungus was able to catch and destroy free-living nematodes and third-stage larvae of Haemonchus contortus added to these plates. Chlamydospores of Arthrobotrys sp. showed a poor resistance to the digestive processes of sheep, although conidia of A. superba survived following oral inoculation in one of two animals.

One hundred and eighty specimens of sigmodontine rodents living in sympatric conditions were collected in the Atlantic Forest in the state of Rio de Janeiro, Brazil (25 Akodon cursor, 98 Akodon montensis and 57 Oligoryzomys nigripes) to examine whether the helminth structure and component communities can be characterized among these three closely related rodents. The parasite species richness was 9 in A. cursor, 12 in A. montensis and 12 in O. nigripes. Five species were common to the three rodent species, and eight were common to A. cursor and A. montensis. The trichostrongylids – Stilestrongylus eta in A. cursor, S. aculeata in A. montensis and S. lanfrediae in O. nigripes – were the species with highest dominance frequency and determined the characterization of individual community structures. The prevalence and abundance of concurrent helminth species among rodents were significantly different. Canonical multivariate analysis demonstrated a similar helminth community structure between A. cursor and A. montensis but a high discrepancy between Akodon spp. and O. nigripes. Thus, the data indicated that small rodents such as A. cursor, A. montenis and O. nigripes that are sympatric and phylogenetically related have a different community structure, but similar component community, suggesting the role of helminth specificity and the hosts' habitats as determinants in structuring their helminth communities.

Ethanol extracts of 25 plant species were screened for anthelmintic effects against Haemonchus contortus. Ethanol extracts of each plant were used at various concentrations (10, 20 and 30%) to treat 10-day faecal cultures, incubated at 27°C with control cultures which were treated with ethanol for 48 h. Five plants with high efficacies (Ananas comosus, Aloe ferox, Allium sativum, Lespedeza cuneata and Warburgia salutaris) were selected from the first screening for further investigation using ethanol, dichloromethane and water extracts at four concentrations (2.5, 5, 10 and 20%). Ethanol was the most effective solvent. Larval counts decreased with increasing extract concentrations, of which 10 and 20% had similar effects. Lespedeza cuneata caused more than 70% mortality at all concentrations. However, there remains a need to assess in vivo efficacy of these plants.

A study of gastrointestinal parasites in 269 faecal samples from dogs (Canis familiaris) collected from Ile-Ife, Nigeria between January and December 2004, revealed seven helminth species: Toxocara canis 33.8%, Ancylostoma sp. 34.6%, Toxascaris leonina 3.3%, Trichuris vulpis 3.7%, Dipylidium caninum 4.1%, Uncinaria stenocephala 0.7% and Taenia sp. 1.1%. The faecal egg intensities, determined as mean eggs per gram of faeces ( ± SEM) were: T. canis 393.8 ± 83.4, Ancylostoma sp. 101.5 ± 32.8, T. leonina 14.3 ± 7.9, T. vulpis 3.4 ± 1.5, D. caninum 2.2 ± 0.8, U. stenocephala 0.2 ± 0.2. The prevalence of intestinal parasites was significantly higher (P < 0.05) in dogs of age 0–6 months than in older age groups. There was no significance difference in overall prevalence of intestinal helminth parasites between male (58.3%) and female (50.0%) dogs (P>0.05). The prevalence of helminth parasites was significantly higher (P < 0.05) in free-ranging than in kennelled dogs. The prevalence of helminth parasites was also significantly higher (P < 0.05) in African shepherds than in Alsatians and other exotic breeds. Each helminth parasite had similar prevalences and intensities among both genders (P>0.05) except in T. vulpis. The overall prevalence of intestinal parasites may continue to rise due to lack of functional veterinary clinics for dog care in Ile-Ife. Therefore, there is the need to establish a veterinary facility in Ile-Ife.

Nematode parasites belonging to the genus Contracaecum are economically important parasites with zoonotic significance. Adult Contracaecum spp. are found in the stomach of marine mammals or piscivorous birds, and larval stages infect a wide range of invertebrates and fish species. Human infection with Contracaecum larvae has been reported in Australia and other countries after the consumption of infected fish. Although the genus Contracaecum comprises numerous species, thus far only four Contracaecum larval types have been specifically identified, therefore their life cycle and biology are not yet fully understood. In this study, a new Contracaecum larva (type IV), found in the intestinal tissue of carp caught from Coonancoocabil Lagoon, New South Wales, Australia, is described and characterized genetically. It was identified as Contracaecum bancrofti, a unique Australian species reported previously from the Australian pelican in Northern Territory, New South Wales, Victoria and South Australia. This study highlights the role of migratory birds and introduced fish species, such as carp, in distributing zoonotic pathogens not only across the continent but also from marine to freshwater systems. Coonancoocabil Lagoon is located in the Murrumbidgee Valley National Park, a highly managed conservation area with native fish in wetlands located in close proximity to several fish farms and hatcheries. Infection of a highly resilient invasive fish species, such as carp, with a zoonotic parasite of low host specificity, such as Contracaecum larvae, should be alarming for aquaculture and environmental authorities.

A data set comprising individual host/parasite lists from 100 Lacerta viridis (Reptilia: Lacertidae) belonging to four isolated populations in Bulgaria was studied. A total of seven helminth species was recovered (Leptophallus nigrovenosus, Plagiorchis molini, Oswaldocruzia filiformis, Spauligodon extenuatus, Skrjabinelazia hoffmanni, Physaloptera clausa and Mesocestoides sp.). Lacerta viridis is a new host record for the first five of these species. Communities of intestinal helminths of L. viridis consist of a few species which resulted in a low species richness, abundance and diversity of infracommunities, which exhibit substantial homogeneity among the four samples. A similar pattern of dominance of two nematode species leading to a relatively high community similarity at both infra- and component community levels was observed. While intestinal helminth communities in lizards from ‘marginal’ habitats were dominated by the host generalist, O. filiformis, those in hosts from ‘typical’ habitats were dominated by the lizard specialist S. extenuatus. The results indicate that the characteristics of the host's habitat are important in determining the composition rather than structure of intestinal helminth communities in L. viridis.

Fasciolopsis buski and Gastrodiscoides hominis are recorded as common human infections in Kamrup District, Assam, where the examination of 221 faecal specimens from different localities gave an average infection rate of 59·7% with F. buski and 41·2% with G. hominis. In individual infections G. hominis may occur in very large numbers; 989 specimens were obtained on one occasion by means of soap water enemas which are effective in removing these worms.

The hygiene hypothesis posits that the decreased incidence of parasitic infection in developed countries may underlie an increased prevalence of allergic and autoimmune diseases in these countries. As unique inflammation modulator of intracellular parasitism, Trichinella spiralis, or its excretory–secretory (ES) product, shows improved responses to allergies, autoimmune diseases, inflammatory bowel disease, type 1 diabetes, rheumatic arthritis and autoimmune encephalomyelitis by exerting immunomodulatory effects on both innate and adaptive immune cells in animal models. Research has shown that T. spiralis differs from other helminths in manipulation of the host immune response not only by well-known characteristics of its life cycle, but also by its inflammation modulation pathway. How the parasite achieves inflammation modulation has not been fully elucidated yet. This review will generalize the mechanism and focuses on ES immunomodulatory molecules of T. spiralis that may be important for developing new therapeutics for inflammatory disorders.

An acute outbreak of Taenia hydatigena cysticercosis, causing mortality in 5 of 21 (23.8%) female lambs, is reported. Gross post-mortem examinations and histology showed Cysticercus tenuicollis as the cause of death. Biochemical parameters in infected lambs confirmed severe hepatitis. Praziquantel, given once at 15 mg/kg body weight (bw), was administered and a dramatic improvement in the clinical condition and biochemical parameters was observed up to 30 days following treatment.

The parasitic fauna of two fish species, namely gill-netted samples of 652 Oreochromis leucostictus and 448 Tilapia zillii from Lake Naivasha and Oloidien Bay was investigated during the period from the end of October 1995 to September 1996. Five larval helminth parasites were recovered including the nematode, Contracaecum sp., the acanthocephalan Polyacanthorhynchus kenyensis, the digenetic trematode, Clinostomum sp. and two cestodes, Amirthalingamia sp. and Cyclustera sp. Both prevalence and intensity of the infection of these helminths increased in larger sized fish, whereas male fish were more heavily infected than females. No seasonality in infection level were observed. The health status of both fish species remained unaffected, although O. leucostictus from Oloidien Bay which harboured heavy infections of Contracaecum exhibited stuntedness and the lack of fatty deposits around the digestive caecum.

Faecal specimens randomly taken from 232 healthy dogs living in the area of Thessaloniki were screened for internal parasites. In 39·2% of the examined dogs excretion of Sarcocystis bovicanis (1·3%), Isospora ohioensis/burrowsi (3·9%), Giardia lamblia (0·8%), Hammondia heydorni (0·4%), Dicrocoelium dendriticum (0·8%) Diplopylidium nolleri (0·4%), Joyeuxiella pasqualei (0·8%), taeniids (0·4%), Toxocara canis (22·4%), Toxascaris leonina (1·3%), Uncinaria stenocephala (3·0%), Trichuris vulpis (2·6%), Spirocerca lupi (0·4%), or Linguatula serrata (0·4%) was detected. The overall rate of infection did not show any significant difference concerning sex or age. T. canis, however, was significantly more often found in the youngest age group (1–3 months).

Canids, particularly dogs, constitute the major source of cystic echinococcosis (CE) infection to humans, with the majority of cases being caused by Echinococcus granulosus (G1 genotype). Canine echinococcosis is an asymptomatic disease caused by adult tapeworms of E. granulosus sensu lato (s.l.). Information on the population structure and genetic variation of adult E. granulosus is limited. Using sequenced data of the mitochondrial cytochrome c oxidase subunit 1 (cox1) we examined the genetic diversity and population structure of adult tapeworms of E. granulosus (G1 genotype) from canid definitive hosts originating from various geographical regions and compared it to that reported for the larval metacestode stage from sheep and human hosts. Echinococcus granulosus (s.s) was identified from adult tapeworm isolates from Kenya, Libya, Tunisia, Australia, China, Kazakhstan, United Kingdom and Peru, including the first known molecular confirmation from Gaza and the Falkland Islands. Haplotype analysis showed a star-shaped network with a centrally positioned common haplotype previously described for the metacestode stage from sheep and humans, and the neutrality indices indicated population expansion. Low Fst values suggested that populations of adult E. granulosus were not genetically differentiated. Haplotype and nucleotide diversities for E. granulosus isolates from sheep and human origin were twice as high as those reported from canid hosts. This may be related to self-fertilization of E. granulosus and/or to the longevity of the parasite in the respective intermediate and definitive hosts. Improved nuclear single loci are required to investigate the discrepancies in genetic variation seen in this study.

Until now Schistosoma mansoni has been regarded as an essentially human parasite. In 1859, Cobbold recorded from Cercocebus fuliginosus a species of Schistosome which he called Bilharzia magna. The only specimen which has been preserved was found to be a fragment of a male by Leiper (1915), who states, “I have been quite unable to identify it with either of the species now recognised in man.” Various authorities have, however, referred this species to S. hœmatobium. S. mansoni has been grown experimentally by Leiper in rats, mice, guinea pigs and African and Indian monkeys, and by Lutz in rabbits. It has never been found naturally in any animal other than man.

Latin America has tripled production by aquaculture up to 78 million tonnes in the past 20 years. However, one of the problems that aquaculture is facing is the presence of helminth parasites and the diseases caused by them in the region. In this review we have collected all the available information on helminths affecting commercial aquaculture in Latin America and the Caribbean (LAC), emphasizing those causing serious economic losses. Monogeneans are by far the most common and aggressive parasites affecting farmed fish in LAC. They have been recognized as serious pathogens in intensive fish culture because they reach high levels of infection rapidly, and can infect other phylogenetically related fish species. The next most important group comprises the larval stages of digeneans (metacercariae) such as Diplostomum sp. and Centrocestus formosanus, which cause serious damage to farmed fish. Since LAC aquaculture has been based mainly on exotic species (tilapia, salmon, trout and carp), most of their parasites have been brought into the region together with the fish for aquaculture. Recently, one of us (A.I.P.-T.) has suggested that monogeneans, which have generally been considered to be harmless, can produce serious effects on the growth of cultured Nile tilapia. Therefore, the introduction of fish together with their ‘harmless’ parasites into new sites, regions or countries in LAC should be considered a breakdown of biosecurity in those countries involved. Therefore, the application of quarantine procedures and preventive therapeutic treatments should be considered before allowing these introductions into a country.

Observations have been made on the survival and migration of infective larvae of strongylid nematodes of the horse deposited on outdoor herbage plots. Few larvae ascended the herbage when conditions were very dry and migration was often enhanced by falls of rain. Larvae on the herbage died rapidly during summer but there was a much slower mortality rate during the winter months. An appreciable proportion of larvae placed on the plots in late summer and autumn survived until the spring but, at this time, there was a rapid disappearance of larvae which coincided with the rising temperatures.