# First report of Ophiotaenia sp. in frogs (Amietophrynus kassasii) from Egypt and in vitro anticestodal activity of Sinularia sp. extract

## TL;DR

This study reports the first case of a tapeworm in Egyptian frogs and shows that a coral extract can effectively kill the parasite in the lab.

## Contribution

The first documentation of Ophiotaenia sp. in Egyptian frogs and evidence of Sinularia sp. extract's anticestodal activity.

## Key findings

- Ophiotaenia sp. was found in 5.9% of frogs with high parasite load and identified using microscopy.
- Sinularia sp. extract killed tapeworms in a dose-dependent manner, with faster mortality at higher concentrations.
- SEM analysis revealed significant structural damage to tapeworms treated with the extract.

## Abstract

Ophiotaenia species are globally distributed proteocephalidean cestodes that commonly parasitize amphibians and reptiles. Despite the ecological importance of frogs in controlling insect populations and maintaining food-web stability, data on cestode infections in Egyptian amphibians remain scarce. This study provides the first documentation of Ophiotaenia sp. infecting Amietophrynus kassasii in Egypt and evaluating the in vitro anticestodal activity of Sinularia sp. extract against adult tapeworms.

A total of 85 frogs were collected from freshwater ponds in New Valley Governorate, Egypt, between February and September 2024. Intestines were examined for cestodes, which were identified morphologically using light microscopy and scanning electron microscopy (SEM). Soft coral Sinularia sp. extract was prepared by methanolic extraction, and three concentrations (25, 50, 100 µg/mL) were assessed for anticestodal efficacy using motility, paralysis, and mortality endpoints. Tapeworms from the control and highest-dose groups were subjected to SEM to evaluate tegumental alterations.

Ophiotaenia sp. infection was detected in 5 of 85 frogs (5.9%), with a notably high mean intensity of 70 parasites per host. The recovered cestodes measured 12–30 mm × 0.7–0.9 mm, featuring a scolex with two spherical suckers and a distinct apical organ. Gut-content analysis of infected frogs revealed coleopteran, orthopteran, and hymenopteran insects as probable intermediate or paratenic hosts. Sinularia sp. extract exhibited clear dose-dependent anticestodal activity. Mortality occurred at 7.58 ± 0.15 h (25 µg/mL), 5.79 ± 0.08 h (50 µg/mL), and 4.247 ± 0.09 h (100 µg/mL), compared with 70.39 ± 1.23 h in controls. SEM analysis of treated cestodes showed profound tegumental erosion, sucker shrinkage, cirrus sac constriction, and proglottid contraction, indicating severe structural disruption.

This study documents the first occurrence of Ophiotaenia sp. in A. kassasii in Egypt and provides evidence that Sinularia sp. extract possesses strong, dose-dependent anticestodal properties. The pronounced tegumental damage observed suggests potent cestocidal mechanisms. These findings offer new insights into amphibian parasitology in Egypt and support the potential development of marine-derived natural products as alternative anthelmintics.