Marshall Lightowlers

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Professor Marshall Lightowlers began his career in the field of parasitology during a post-doctoral appointment at the Institute of Medical and Veterinary Science in Adelaide where he undertook research on ovine sarcocystosis. In 1981 he began a post-doctoral position at The University of Melbourne, Veterinary Clinical Centre and commenced a research career focusing on the immunology and molecular biology of taeniid cestode parasites. His initial research at the University of Melbourne investigated the immunochemistry of antigens of Taenia taeniaeformis and Echinococcus granulosus . Subsequently he was a member of a team of scientists that developed a vaccine against Taenia ovis infection in sheep, [1] the first recombinant vaccine against a parasitic disease. [2] In 1989 Lightowlers took over leadership of the molecular parasitology research laboratories at the University of Melbourne and began applying the lessons learnt with T. ovis to the development of similar vaccines against infection with the larval stages of other cestode parasites. This led to the development of highly effective, recombinant vaccines against cysticercosis in cattle due to Taenia saginata (TSA9/TSA18) [3] and in pigs due to Taenia solium . [4] [5] In collaboration with Dr David Heath at the Wallaceville Animal Research Centre in New Zealand, he and his colleagues also developed the EG95 recombinant vaccine against cystic echinococcosis (hydatid disease). [6]

The E. granulosus and T. solium vaccines could potentially have been developed for use directly in humans, however due to the parasites’ medical impact being restricted largely to developing countries, funding was not forthcoming, hence they were developed for use in the parasites’ natural animal intermediate hosts. Use of the vaccines in this way would reduce the parasites' transmission and, indirectly, the incidence of cystic echinococcosis and neurocysticercosis in humans.

The EG95 vaccine was proven successful in experimental trials in sheep against E. granulosus infection carried out in Argentina, China, Romania, Iran, New Zealand and Australia. [7] The vaccine was registered as a commercial product in China in 2007 by Chongqing Auleon Biologicals Co., Ltd., and in Argentina in 2011 by Tecnovax Sanidad Animal. In 2016 the EG95 vaccine was incorporated into the Chinese National Echinococcosis Control Program and National Animal Disease Compulsory Immunization Program. [8] [9]

The TSOL18 vaccine against Taenia solium achieved >99% protection in experimental trials undertaken in pigs in Mexico, Cameroon and Peru. [7] It has been developed as a commercial product, Cysvax, by Indian Immunologicals Limited and registered in India in 2016. The TSOL18 vaccine played an important role in a large-scale, successful, cysticercosis elimination program undertaken in the Tumbes region of northern Peru. [10] The vaccine has completed the clinical trials in Nepal and has shown to be effective to control cysticercosis in pigs of the region.

Marshall Lightowlers is Principal Research Fellow with the National Health and Medical Research Council in Australia and Professor in the Faculty of Veterinary and Agricultural Sciences at the University of Melbourne. In 2011 he was appointed by the University of Melbourne Council as Melbourne Laureate Professor. He has published more than two hundred articles in internationally refereed journals and books. He has been an active member of the Australian Society for Parasitology, serving as the society's President in 1995/6, Honorary Secretary, and as a council member representing Victoria. In 1998 the society awarded Lightowlers the Bancroft-Mackerras Medal in recognition of his outstanding contribution to the science of parasitology.

Related Research Articles

<span class="mw-page-title-main">Echinococcosis</span> Parasitic disease of tapeworms of the Echinococcus type

Echinococcosis is a parasitic disease caused by tapeworms of the Echinococcus type. The two main types of the disease are cystic echinococcosis and alveolar echinococcosis. Less common forms include polycystic echinococcosis and unicystic echinococcosis.

Veterinary parasitology is a branch of veterinary medicine that deals with the study of morphology, life-cycle, pathogenesis, diagnosis, treatment, and control of eukaryotic invertebrates of the kingdom Animalia and the taxon Protozoa that depend upon other invertebrates and higher vertebrates for their propagation, nutrition, and metabolism without necessarily causing the death of their hosts. Modern parasitology focuses on responses of animal hosts to parasitic invasion. Parasites of domestic animals,, as well as wildlife animals are considered. Data obtained from parasitological research in animals helps in veterinary practice and improves animal breeding. The major goal of veterinary parasitology is to protect animals and improve their health, but because a number of animal parasites are transmitted to humans, veterinary parasitology is also important for public health.

<span class="mw-page-title-main">Cysticercosis</span> Tissue infection caused by the young form of the pork tapeworm

Cysticercosis is a tissue infection caused by the young form of the pork tapeworm. People may have few or no symptoms for years. In some cases, particularly in Asia, solid lumps of between one and two centimetres may develop under the skin. After months or years these lumps can become painful and swollen and then resolve. A specific form called neurocysticercosis, which affects the brain, can cause neurological symptoms. In developing countries this is one of the most common causes of seizures.

<i>Taenia solium</i> Species of Cestoda

Taenia solium, the pork tapeworm, belongs to the cyclophyllid cestode family Taeniidae. It is found throughout the world and is most common in countries where pork is eaten. It is a tapeworm that uses humans as its definitive host and pigs as the intermediate or secondary hosts. It is transmitted to pigs through human feces that contain the parasite eggs and contaminate their fodder. Pigs ingest the eggs, which develop into larvae, then into oncospheres, and ultimately into infective tapeworm cysts, called cysticercus. Humans acquire the cysts through consumption of uncooked or under-cooked pork and the cysts grow into an adult worms in the small intestine.

<i>Taenia</i> (tapeworm) Genus of flatworms

Taenia is the type genus of the Taeniidae family of tapeworms. It includes some important parasites of livestock. Members of the genus are responsible for taeniasis and cysticercosis in humans, which are types of helminthiasis belonging to the group of neglected tropical diseases. More than 100 species are recorded. They are morphologically characterized by a ribbon-like body composed of a series of segments called proglottids; hence the name Taenia. The anterior end of the body is the scolex. Some members of the genus Taenia have an armed scolex ; of the two major human parasites, Taenia saginata has an unarmed scolex, while Taenia solium has an armed scolex.

<i>Taenia saginata</i> Species of flatworm

Taenia saginata, commonly known as the beef tapeworm, is a zoonotic tapeworm belonging to the order Cyclophyllidea and genus Taenia. It is an intestinal parasite in humans causing taeniasis and cysticercosis in cattle. Cattle are the intermediate hosts, where larval development occurs, while humans are definitive hosts harbouring the adult worms. It is found globally and most prevalently where cattle are raised and beef is consumed. It is relatively common in Africa, Europe, Southeast Asia, South Asia, and Latin America. Humans are generally infected as a result of eating raw or undercooked beef which contains the infective larvae, called cysticerci. As hermaphrodites, each body segment called proglottid has complete sets of both male and female reproductive systems. Thus, reproduction is by self-fertilisation. From humans, embryonated eggs, called oncospheres, are released with faeces and are transmitted to cattle through contaminated fodder. Oncospheres develop inside muscle, liver, and lungs of cattle into infective cysticerci.

<i>Echinococcus</i> Genus of worms

Echinococcus is a genus within Cestoda, a parasitic class of the platyhelminthes phylum. Human echinococcosis is an infectious disease caused by the following species: E. granulosus, E. multilocularis, or E. vogeli.

<i>Echinococcus granulosus</i> Species of flatworm

Echinococcus granulosus, also called the hydatid worm, hyper tape-worm or dog tapeworm, is a cyclophyllid cestode that dwells in the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and humans, where it causes cystic echinococcosis, also known as hydatid disease. The adult tapeworm ranges in length from 3 mm to 6 mm and has three proglottids ("segments") when intact—an immature proglottid, mature proglottid and a gravid proglottid. The average number of eggs per gravid proglottid is 823. Like all cyclophyllideans, E. granulosus has four suckers on its scolex ("head"), and E. granulosus also has a rostellum with hooks. Several strains of E. granulosus have been identified, and all but two are noted to be infective in humans.

<i>Echinococcus multilocularis</i> Species of flatworm

Echinococcus multilocularis, the fox tapeworm, is a small cyclophyllid tapeworm found extensively in the northern hemisphere. E. multilocularis, along with other members of the Echinococcus genus, produce diseases known as echinococcosis. Unlike E. granulosus,E. multilocularis produces many small cysts that spread throughout the internal organs of the infected animal. The resultant disease is called Alveolar echinococcosis, and is caused by ingesting the eggs of E. multilocularis.

<i>Taenia crassiceps</i> Species of Cestoda

Taenia crassiceps is a tapeworm in the family Taeniidae. It is a parasitic organism whose adult form infects the intestine of carnivores, like canids. It is related to Taenia solium, the pork tapeworm, and to Taenia saginata, the beef tapeworm. It is commonly found in the Northern Hemisphere, especially throughout Canada and the northern United States.

<span class="mw-page-title-main">Taeniidae</span> Family of flatworms

The Taeniidae are a family of tapeworms. It is the largest family representing the order Cyclophyllidea. It includes many species of medical and veterinary importance, as Taenia solium, Taenia saginata, and Echinococcus granulosus. The Taeniidae are parasites of mammals and many are infectious to humans.

<i>Taenia pisiformis</i> Species of flatworm

Taenia pisiformis, commonly called the rabbit tapeworm, is an endoparasitic tapeworm which causes infection in lagomorphs, rodents, and carnivores. Adult T. pisiformis typically occur within the small intestines of the definitive hosts, the carnivores. Lagomorphs, the intermediate hosts, are infected by fecal contamination of grasses and other food sources by the definitive hosts. The larval stage is often referred to as Cysticercus pisiformis and is found on the livers and peritoneal cavities of the intermediate hosts. T. pisiformis can be found worldwide.

<span class="mw-page-title-main">Taeniasis</span> Parasitic disease due to infection with tapeworms belonging to the genus Taenia

Taeniasis is an infection within the intestines by adult tapeworms belonging to the genus Taenia. There are generally no or only mild symptoms. Symptoms may occasionally include weight loss or abdominal pain. Segments of tapeworm may be seen in the stool. Complications of pork tapeworm may include cysticercosis.

<span class="mw-page-title-main">Eucestoda</span> Subclass of flatworms

Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda. Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodaria. All tapeworms are endoparasites of vertebrates, living in the digestive tract or related ducts. Examples are the pork tapeworm with a human definitive host, and pigs as the secondary host, and Moniezia expansa, the definitive hosts of which are ruminants.

<span class="mw-page-title-main">Neurocysticercosis</span> Cysticercosis of the brain

Neurocysticercosis is a specific form of the infectious parasitic disease cysticercosis that is caused by the infection with Taenia solium, a tapeworm found in pigs. Neurocysticercosis occurs when cysts formed by the infection take hold within the brain, causing neurologic syndromes such as epileptic seizures. It is a common cause of seizures worldwide. It has been called a "hidden epidemic" and "arguably the most common parasitic disease of the human nervous system". Common symptoms of neurocysticercosis include seizures, headaches, blindness, meningitis and dementia.

Human parasites include various protozoa and worms.

Taenia asiatica, commonly known as Asian taenia or Asian tapeworm, is a parasitic tapeworm of humans and pigs. It is one of the three species of Taenia infecting humans and causes taeniasis. Discovered only in 1980s from Taiwan and other East Asian countries as an unusual species, it is so notoriously similar to Taenia saginata, the beef tapeworm, that it was for a time regarded as a slightly different strain. But anomaly arose as the tapeworm is not of cattle origin, but of pigs. Morphological details also showed significant variations, such as presence of rostellar hooks, shorter body, and fewer body segments. The scientific name designated was then Asian T. saginata. But the taxonomic consensus turns out to be that it is a unique species. It was in 1993 that two Korean parasitologists, Keeseon S. Eom and Han Jong Rim, provided the biological bases for classifying it into a separate species. The use of mitochondrial genome sequence and molecular phylogeny in the late 2000s established the taxonomic status.

Taenia serialis, also known as a canid tapeworm, is found within canines such as foxes and dogs. Adult T. serialis are parasites of carnivores, particularly dogs, with herbivorous lagomorph mammals such as rabbits and hares, serving as intermediate hosts. In definitive hosts, T. serialis is acquired by eating tissues from a variety of intermediate hosts. Accidental infection of humans though, can occur when eggs are ingested from food or water contaminated with dog feces and the human then becomes the T. serialis intermediate host.

<i>Taenia hydatigena</i> Species of flatworm

Taenia hydatigena is one of the adult forms of the canine and feline tapeworm. This infection has a worldwide geographic distribution. Humans with taeniasis can infect other humans or animal intermediate hosts by eggs and gravid proglottids passed in the feces.

<span class="mw-page-title-main">Cysticercus</span> Larval tapeworm

Cysticercus is a scientific name given to the young tapeworms (larvae) belonging to the genus Taenia. It is a small, sac-like vesicle resembling a bladder; hence, it is also known as bladder worm. It is filled with fluid, in which the main body of the larva, called scolex, resides. It normally develops from the eggs, which are ingested by the intermediate hosts, such as pigs and cattle. The tissue infection is called cysticercosis. Inside such hosts, they settle in the muscles. When humans eat raw or undercooked pork or beef that is contaminated with cysticerci, the larvae grow into adult worms inside the intestine. Under certain circumstances, specifically for the pork tapeworm, the eggs can be accidentally eaten by humans through contaminated foodstuffs. In such case, the eggs hatch inside the body, generally moving to muscles as well as inside the brain. Such brain infection can lead to a serious medical condition called neurocysticercosis. This disease is the leading cause of acquired epilepsy.

References

  1. ↑ Johnson, K.S., Harrison, G.B., Lightowlers, M.W., O'Hoy, K.L., Cougle, W.G., Dempster, R.P., Lawrence, S.B., Vinton, J.G., Heath, D.D. & Rickard, M.D., 1989. Vaccination against ovine cysticercosis using a defined recombinant antigen. Nature,338, 585-587.
  2. ↑ Cox, F.E.G., 1993. Milestones in parasitology. Parasitology Today9, 347-348.
  3. ↑ Lightowlers, M.W., Rolfe, R. & Gauci, C.G., 1996. Taenia saginata: vaccination against cysticercosis in cattle with recombinant oncosphere antigens. Experimental Parasitology84, 330-338.
  4. ↑ Flisser, A., Gauci, C.G., Zoli, A., Martinez-Ocana, J., Garza-Rodriguez, A., Dominguez-Alpizar, J.L., Maravilla, P., Rodriguez-Canul, R., Avila, G., Aguilar-Vega, L., Kyngdon, C., Geerts, S. & Lightowlers, M.W., 2004. Induction of protection against porcine cysticercosis by vaccination with recombinant oncosphere antigens. Infection & Immunity72, 5292-5297.
  5. ↑ Gonzalez, A.E., Gauci, C.G., Barber, D., Gilman, R.H., Tsang, V.C., Garcia, H.H., Verastegui, M. & Lightowlers, M.W., 2005. Vaccination of pigs to control human neurocysticercosis. American Journal of Tropical Medicine and Hygiene72, 837-839.
  6. ↑ Lightowlers, M.W., Lawrence, S.B., Gauci, C.G., Young, J., Ralston, M.J., Maas, D. & Health, D.D., 1996. Vaccination against hydatidosis using a defined recombinant antigen. Parasite Immunology18, 457-462.
  7. 1 2 Lightowlers, M.W., 2006. Cestode vaccines: origins, current status and future prospects. Parasitology133, S27-42.
  8. ↑ Yuan, R., Wu, H., Zeng, H., Liu, P., Xu, Q., Gao, L., Li, Y., Li, R., Huang, D., Yu, C. & Sun, X., 2017. Prevalence of and risk factors for cystic echinococcosis among herding families in five provinces in western China: a cross-sectional study. Oncotarget8, 91568-91576.
  9. ↑ "2017 National Animal Disease Compulsory Immunization Program".
  10. ↑ Garcia, H.H., Gonzalez, A.E., Tsang, V.C., O'Neal, S.E., Llanos-Zavalaga, F., Gonzalvez, G., Romero, J., Rodriguez, S., Moyano, L.M., Ayvar, V., Diaz, A., Hightower, A., Craig, P.S., Lightowlers, M.W., Gauci, C.G., Leontsini, E., Gilman, R.H., Cysticercosis Working Group in, P., 2016. Elimination of Taenia solium transmission in Northern Peru. New England Journal of Medicine374, 2335-2344.
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