Toadfishes are found in tropical, marine, and estuarine waters. They have a highly developed venomous apparatus with dorsal and preopercular spines (Figure 1). Envenomation by this species can cause local inflammatory manifestations such as pain, edema, and erythema that can progress to cutaneous necrosis.1–5
Evolution of patient envenomation, from the initial inflammation and hemorrhagic blistering (left) to the skin necrosis with ulcer (right). The process lasted about a month. Photos: Vidal Haddad Jr.
Citation: The American Journal of Tropical Medicine and Hygiene 101, 3; 10.4269/ajtmh.19-0321
A 38-year-old woman stepped on something in a lagoon among the stones of a beach in Bahia state, Brazil. She then noticed two small perforations in the third toe of the right foot with slight bleeding. The place began to ache unbearably and she was medicated with painkillers. After 3 days, intense inflammation and hemorrhagic blisters appeared near to the perforations. In about 10 days, the upper blister delimited a necrosis and the formation of an ulcer covered by hemato-meliceric crust (Figure 2). The pain, which had persisted for about a week, had disappeared. One month later, ulcer was healed, leaving a scar.
Live specimens of the toadfish Thalassophryne nattereri, with one of them semi-buried in the sand in a typical position. In the details, dorsal spicules of the fish, responsible for inoculation of the venom. Photos: Vidal Haddad Jr.
Citation: The American Journal of Tropical Medicine and Hygiene 101, 3; 10.4269/ajtmh.19-0321
Wounds by venomous fishes can be difficult to identify. Catfishes and stingrays cause mainly unique perforations, but the envenomation by toadfishes causes a characteristic double perforation by the dorsal spicules. The species present in the region is Thalassophryne nattereri, the “niquim.”3–5
The initial treatment is the immersion of the place in hot water for 30–90 minutes. Treatment with warm water minimizes pain intensity.5 Bacterial infection is common.5
REFERENCES
- 1.↑
Fróes HP, 1932. Sur un poisson toxiphore brésilien: le “niquim” Thalassophryne maculosa. Rev Sud Am Med Chil 3: 871–878.
- 2.
Lopes-Ferreira M, Barbaro KC, Cardoso DF, Moura-Da-Silva AM, Mota I, 1998. Thalassophryne nattereri fish venom: biological and biochemical characterization and serum neutralization of its toxic activities. Toxicon 36: 405–410.
- 3.↑
Lima LAF, Lopes-Ferreira M, 2000. Estudo clínico e experimental sobre o envenenamento causado pelo peixe Thalassophryne nattereri (niquim). An Bras Dermatol 75: 435–443.
- 4.
Haddad Jr V, Pardal PPO, Cardoso JLC, Martins IA, 2003. The venomous toadfish Thalassophryne nattereri (niquim or miquim): report of 43 injuries provoked in fishermen of Salinópolis (Pará State) and Aracaju (Sergipe State), Brazil. Rev Inst Med Trop São Paulo 45: 221–223.
- 5.↑
Haddad V Jr., 2016. Medical Emergencies Caused by Aquatic Animals: A Zoological and Clinical Guide. Geneva, Switzerland: Springer Publishers.