Results and discussion

In this study, we report four confirmed cases of T. saginata taeniasis from Aragua state, Venezuela. The four patients were female and from four different, geographically separated urban municipalities; specifically, patient 1 was from Francisco Linares Alcántara, patient 2 was from Sucre, patient 3 was from Libertador and patient 4 was from Girardot. Although patients 1, 2 and 3 had never been outside their municipalities, patient 4 had been in Colombia for one month a year prior to her treatment.

All the patients had bought their meat at local butchers and had sought medical consultation for the following reasons: (1) expulsion of faecal proglottids (all four patients); (2) abdominal pain, diarrhoea, reflux/dyspepsia and epigastric pain (patients 1, 2 and 4); (3) weight loss (patient 4). Significantly, patients 1, 2 and 3 admitted consuming raw meat during the process of preparing their meals; the other said that she had not knowingly consumed raw meat. All the patients were successfully treated with praziquantel without recurrence up to four months post treatment.

Eggs and gravid proglottids of Taenia spp. were detected in the stools of all four patients. After subsequent treatment, adult worms were expelled by all the patients and measured 1.4–6.0 metres long. Scolices were only recovered from patients 1 and 4. The quantification of uterine branches of the gravid proglottids confirmed the parasite to be T. saginata in all four cases, in agreement with a similar conclusion from the examination of the scolices recovered from patients 1 and 4. Finally, the PCR analysis provided unambiguous identification of T. saginata (fig. 1). Thus, amplification of the DNA of all four patients yielded the 170 and 600 nucleotide components characteristic of T. saginata. (fig. 1).

Fig. 1.

Amplification products obtained by multiplex PCR from proglottid DNA. Molecular weight marker (M), T. solium DNA positive control (1); T. saginata DNA positive control (2); DNA sample patient 1 (3); DNA sample patient 2 (4); DNA sample patient 3 (5); DNA sample patient 4 (6); negative control (7). The number of nucleotides is given in the ordinal. Nucleotide sequences of 170 and 600 bases are amplified from the DNA of T. saginata, whereas only the 170 base band is amplified from T. solium DNA. Details in Materials and methods.

Post treatment parasitological examination of the stools of patients 1, 2 and 3, detected the presence of Taenia spp. eggs at day 3. Thereafter, all the samples (until four months) were negative for Taenia eggs. Similarly, coprological examination of the patients’ families failed to detect Taenia eggs, although family members of patients 1 and 3 were infected with Trichuris trichura and Blastocystis hominis respectively. The family members of patient 4 did not provide a faecal sample.

In conclusion, we have reported four confirmed cases of T. saginata taeniasis in urban zones of the Aragua state. The fact that each infected individual lives in geographically distinct urbanizations makes it unlikely that infections had a common origin, and suggests a problem in the efficiency of meat inspection that demands urgent attention, as indeed has recently confirmed by Rodrigo Agudo, the food assessor for FEDENAGA (Federación Nacional de Ganaderos, Venezuela) (Notitarde, 31 October 2018).