Multiplex PCR for Differential Identification of Broad Tapeworms (Cestoda:Diphyllobothrium) Infecting Humans

Abstract

The specific identification of broad tapeworms (genus Diphyllobothrium) infecting humans is very difficult to perform by morphological observation. Molecular analysis by PCR and sequencing represents the only reliable tool to date to identify these parasites to the species level. Due to the recent spread of human diphyllobothriosis in several countries, a correct diagnosis has become crucial to better understand the distribution and the life cycle of human-infecting species as well as to prevent the introduction of parasites to disease-free water systems. Nevertheless, PCR and sequencing, although highly precise, are too complicated, long, and expensive to be employed in medical laboratories for routine diagnostics. In the present study we optimized a cheap and rapid molecular test for the differential identification of the most common Diphyllobothrium species infecting humans (D. latum, D. dendriticum, D. nihonkaiense, and D. pacificum), based on a multiplex PCR with the cytochrome c oxidase subunit 1 gene of mitochondrial DNA.

Diphyllobothrium pacificum Infection is Seldom Associated with Megaloblastic Anemia

“…In two published studies using polymerase chain reaction, all specimens (n = 8) collected in Peru were D. pacificum. 6,7 Spontaneous elimination of Diphyllobothrium tapeworms occurred in seven (35%) of our patients, which is consistent with the rate of 25% reported in the literature. In all patients, treatment or spontaneous worm expulsion were followed by negative fecal examination results at 30 days.…”

“…However, molecular techniques have been extensively used to differentiate Diphyllobothrium spp. 6,7 Symptoms of infection are mild and include abdominal pain, bloating, diarrhea, anorexia, headaches, constipation, and vomiting.…”

Molecular Testing for Clinical Diagnosis and Epidemiological Investigations of Intestinal Parasitic Infections

“…Species-specific PCRs for non-Taenia tapeworm species (407). PCR followed by sequencing using universal primers to amplify the ribosomal ITS1, ITS2, 5.8S, and SSU rDNA sequences or mitochondrial genes is used to identify and confirm the species identity of tapeworms found in individual cases as well as interspecies variation to construct phylogenetic relationships (408)(409)(410)(411).…”

Molecular identification of Diphyllobothrium latum and a brief review of diphyllobothriosis in China

“…In our study, more than 6% exists between cox1 sequences of D. latum and other species, and more than 10% divergence exists between nad5 nucleotide sequences, indicating that they are suitable molecular targets for the characterization of D. latum. Other mitochondrial genes may also be useful to classify species that infect humans (Yera et al 2008, Scholz et al 2009, Wicht et al 2010.…”