Page 1 of 9
European Journal of Applied Sciences – Vol. 9, No. 6
Publication Date: December 25, 2021
DOI:10.14738/aivp.96.11186. Salim, M., Masroor, M. S., Parween, S., & Singh, A. (2021). An Overview on Human Helminthic Parasitology III. Cestodes, the
Tapeworms. European Journal of Applied Sciences, 9(6). 80-88.
Services for Science and Education – United Kingdom
An Overview on Human Helminthic Parasitology III. Cestodes, the
Tapeworms
Mohammad Salim
Sanjay Gandhi Smriti Govt. Autonomous P.G.
College, Sidhi, A.P.S. University, Rewa (M.P.), India
Mohammad Shahid Masroor
People’s College of Dental Sciences & Research Center
People’s University, Bhopal (M.P.), India
Shagufta Parween
Deptt. of Human Anatomy
All India Institute of Medical sciences (AIIMS), Bhopal (M.P.) India
Amrita Singh
Sanjay Gandhi Smriti Govt. Autonomous P.G.
College, Sidhi, A.P.S. University, Rewa (M.P.), India
ABSTRACT
Helminths developed a variety of diseases in humans. They are invertebrate
animals usually found in the intestines of the hosts. Cestodes in association with
normal ailments and diseases caused by them, they infrequently produce some
other specific diseases like cysticercosis, neurocysticercosis and hydatid diseases
in humans. The present review is third in the series of helminthic parasitology
discussing some of the Cestodes in the light of recent researches done so far in the
same field.
Keywords : Parasitology, Helminths, Cestodes, Tapeworms, Diseases and malignancies in
human.
INTRODUCTION
Helminths are popularly known as the worms. They basically divided into Nemathelminths
(Nematoda, the roundworms) and Platyhelminthes (Trematoda, the flatworms and flukes) and
(Cestodes, the tapeworms). Cestodes are tape or ribbon like bilaterally symmetrical and
dorsiventral, intestinal, triploblastic, hermaphroditic, oviparous and segmented metazoans
whose body parts are divided into scolex, neck and strobila. While they have suckers and hooks
in their heads, the strobila is made of proglottids. The neck acts like a growing region. This is
actively engaged in producing the proglottids one by one. And, the last gravid proglottid is often
detached to disseminate the eggs. Sometimes, they are very big in their lengths. These are
generally found in mammals like dogs, sheep, beef including humans and fishes causing
diseases as cysticercosis, neurocysticercosis and hydatid diseases in humans. The present
review discusses as under some of the Cestodes causing diseases in humans like Taenia solium,
a pork tapeworm as neurocysticercosis; Diphyllobothrium latum, a fish tapeworm as
Page 3 of 9
82
European Journal of Applied Sciences (EJAS) Vol. 9, Issue 6, December-2021
Services for Science and Education – United Kingdom
immunoblot, ELISA and PCR are also available to confirm the infection. In addition, while X rays
are used to detect the dead and calcified larvae in the subcutaneous and muscle tissue, the CT
scans and MRIs are conducted to find out the larvae and lesions in the brain (Richards and
Schantz 1991, Guezala et al. 2009, Hernandez et al. 2017)[17-19].
Further, the infection can be prevented with proper disposal of human fecal matter and by
avoiding the ingestion of undercooked meat and vegetables contaminated with cysts and eggs.
While niclosamide is a drug of choice for simple taeniasis, praziquantel is used for cysticercosis.
In neurocysticercosis, albendazole and praziquantel are used. Albendazole with corticosteroids
is given to reduce the inflammation. Sometimes, the surgical removal of cysts is also performed
with proper medications provided (Gonzalez et al. 2003, white 2009, Gilman et al. 2012, Garcia
et al. 2016, Mc Clugage et al. 2017)[20-24]. Lastly, the development of S3Pvac vaccine is developed
for the control of cysticercosis caused by the Taenia solium (Sciutto et al. 2013)[25].
Diphyllobothrium latum (Diphyllobothriasis)
Diphyllobothrium latum is a broad fish tapeworm causing diphyllobothriasis in human. This is
mostly found in places where raw fishes are eaten regularly (Tomas et al. 2009)[26]. This is
native to Scandinavia, western Russia and Baltics. Currently, it has also been reported from east
Asian countries like Japan, Korea, China and Taiwan and some other places like north and south
America, Uganda, Peru, Chile and Serbia (Tomas et al. 2009)[26]. In India, the only case was
reported from south India in 2011 (Ramana et al. 2011)[27]. The definitive hosts of
Diphyllobothrium latum are piscivorous mammals including human and some birds
representing the significant zoonotic reservoirs. The intermediate hosts are some crustaceans
and fishes (Durrani et al. 2021)[9].
D. latum is an hermaphroditic animal measuring about 4 to 15 meters long. The entire body is
divided into scolex, neck and the lower body. In scolex, on each side, the device bothrium
attaches to the intestine. The neck is a proliferative region of proglottids. Each proglottid is
wider enough to contain a set of both reproductive organs opening midventrally into a genital
pore. The adults are developed inside the small intestine. These proglottids are detached and
the immature unembryonated eggs are released in feces contaminating the freshwater to start
the cycle. These eggs are matured and being eaten by the crustaceans and then fishes. Finally,
when these infected fishes are consumed by the humans, the larvae thus developed reach the
small intestine where they mature to repeat the cycle again. An adult worm produces
approximately 1 million eggs per day. And, the incubation period of the disease is about 4 to 6
weeks (Sampaio et al. 2005, Durrani et al. 2021)[9, 28].
As the symptoms are either mild or asymptomatic, the disease has never been taken seriously
and if untreated the infections may be long lasting persisting for up to even 25 years. Some of
the clinical manifestations are abdominal distension, pain and discomfort, constipation,
diarrhea, nausea, vomiting, weight loss, fatigue, headache, myalgia and dizziness. Sometimes,
the D. latum infection is mimicking as the subacute appendicitis. Similarly, the parasite is
thought to cause changes as immunomodulators developing some structural changes in GI tract
modulating some endocrine responses to enhance the gut secretions and motility. The worm
also causes the mast cell and eosinophil degradation leading to the release of proinflammatory