CASE REPORTS AAEM Ann Agric Environ Med 2008, 15, 163–166

CATFISH STINGS AND THE VENOM APPARATUS OF THE AFRICAN CATFISH CLARIAS GARIEPINUS (BURCHELL, 1822), AND STINGING CATFISH HETEROPNEUSTES FOSSILIS (BLOCH, 1794)

Leszek Satora1, Michał Kuciel1, Tomasz Gawlikowski2

1Poison Information Centre, Collegium Medicum, Jagiellonian University Kraków, Poland 2Clinic of Toxicology Collegium Medicum, Jagiellonian University Kraków, Poland

Satora L, Kuciel M, Gawlikowski T: Catfi sh stings and the venom apparatus of the Af- rican catfi sh Clarias gariepinus (Burchell, 1822), and stinging catfi sh Heteropneustes fossilis (Bloch, 1794). Ann Agric Environ Med 2008, 15, 163–166.

Abstract: The ability of catfi sh to infl ict extremely painful wounds with their pectoral and dorsal stings has been well known for many decades. The venom apparatus of the African catfi sh Clarias gariepinus (Burchell, 1822), and stinging catfi sh Heteropneustes fossilis (Bloch, 1794) is constituted by a single, sharp and stout sting immediately in front of the soft-rayed portion of the pectoral fi ns. The sting has well developed articula- tions, making it possible for it to become erect and locked. The toxicological centres in Poland have recorded 17 cases of envenomations caused by stinging catfi sh and African catfi sh; the injury was accompanied by intense pain, numbness of the site, dizziness, lo- cal oedema and erythema. In addition, systemic symptoms such as tachycardia, weakness and arterial hypotension were observed. The treatment of these injuries should include cleansing of the wound and surrounding area. Immersion of the wounded extremity in hot water (45°C) was used for the pain control. An attempt to remove any spinal sheath or remnant must be undertaken. Antibiotic management depends on several factors: the age and immune status of the victim, the interval between injury and presentation, or the presence of a foreign body. The most serious long-term complications of sting envenoma- tion involve infections.

Address for correspondence: Dr Leszek Satora, Poison Information Centre, Collegium Medicum, Jagiellonian University, Os. Złotej Jesieni 1, 31-826 Kraków, Poland. E-mail: [email protected]

Key words: freshwater catfi sh, stings, envenomation.

INTRODUCTION wounds with their pectoral and dorsal stings has been well known for many decades. Catfi sh sting envenomation is Venomous catfi sh have a sharp and stout sting immedi- a frequent cause of morbidity among anglers, fi shermen, ately in front of the soft-rayed portion of the pectoral and food processors and aquarists [1, 2, 4, 6, 7, 10, 11]. Catfi sh dorsal fi ns. Stings are derived from fi n rays, and are cov- have two toxicity mechanisms: the fi rst is linked to sting ered by a thin integumentary sheath. There is no external penetration and rupture of the venom glandular tissue sur- sign of the venom glands, which are located in a series of rounding the sting, whereas the second, called crinotoxic- sharp, recurving teeth capable of cutting into a victim’s ity, is associated with the production of toxins in the entire fl esh, helping the venom to be absorbed and often seeding fi sh skin [3]. The venom of catfi sh is a complex compo- serious infections. The stings of the catfi sh are very dan- sition of haemolytic, dermonecrotic, oedema-producing gerous once they have been erect. In catfi sh, the pectoral and vasospastic factors whose potency is largely inversely fi ns aid the fi sh in its defence mechanism against preda- proportional to the fi sh size, and is a defensive mechanism tors [5, 7]. The ability of catfi sh to infl ict extremely painful [1, 2]. In some fi sh, single-cell glands may be grouped in

Received: 28 August 2007 Accepted: 6 April 2008 164 Satora L, Kuciel M, Gawlikowski T larger aggregates of cells called venom glands that may catfi sh in the monitored areas; 10 caused by stinging catfi sh form organs resembling multicellular glands of terrestrial and 7 caused by African catfi sh. Observations were carried animals. They are usually located around the spines or hard out in the years 2003–2007. Medical history was collected rays, of the fi n. Even if covered with a connective tissue from patients who had to answer a questionnaire related to sheath, the aggregates of the venom cells do not have any the epidemiological and clinical aspects of envenomation. common outlet; they are not therefore proper multicellular The course of poisoning was analysed on the basis of case glands. The venom glands of catfi sh are covered with a thin records and correlated with the catfi sh venom composition. sheath and release their contents when the sting is pressed. Three African catfi sh and 3 stinging catfi sh were used for When the sting penetrates the body of its prey, pressure and the analysis of the pectoral stings. The fi sh were killed after rupture of the glandular tissue cause venom penetration of anesthesia in triacaine (MS 222) solution. The pectoral fi ns the wound. [1, 2, 10]. The African catfi sh is a fi sh with an were separated and each of them observed under a light elongated body that is smooth and very fl exible. It has a microscope. long dorsal fi n without a sting. Stings occur in the pectoral fi ns. This species has venom glands organized similarly to RESULTS stinging catfi sh (masses of single-cell glands, mainly se- rous, in the proximity of the stings located near the spine Seven cases of envenomation with African catfi sh ven- of the pectoral spine [3]. This family is widely distributed om were reported. The exposure took place during contact throughout Africa, India, Indonesia and Indochina. It has with the stings of the pectoral fi ns. The affected persons an organ for breathing with air, which is a gill chamber, were staff of supermarkets, and injuries occurred during broader in its upper part, fi lled with bush-like upward-di- fi sh preparation for sale. Injuries were puncture wounds in rected protrusions of the second and fourth gill arcs. Clari- all cases. The wounds were on the right hand in 5 victims, as gariepinus, which is generally considered to be one of left hand in 2. Intense pain was the main symptom in the the most important tropical catfi sh species for aquaculture, acute phase of envenoming, but other infl ammation mani- has an almost Pan-African distribution, ranging from the festations, such as oedema and erythema, were also com- Nile to West Africa and from Algeria to South Africa. They mon in all cases. Treatment consisted of surgical wound also occur in Asia Minor (Israel, Syria and southern Tur- debridement, and removal of the remnants of broken fi n key). In general, C. gariepinus lives in most river basins rays in 2 cases, hot water immersion for 40 min. in 5 cases sympatrically with C. anguillaris (L). Heteropneustes fos- as well as pain management, antibiotic therapy and teta- silis commonly known as stinging catfi sh, the only species nus prophylaxis were given in all cases. Over 1-2 months, belonging to the family Heteropneustidae found in Asia. In the wound healed slowly by second intention. No residual their natural environment the fi sh can reach up to 70 cm in defi cits in motor or sensory functions were observed. Aid length; however when bred in an aquarium they are signifi - was usually provided by fi rst-contact physicians in 4 cases cantly smaller [10]. Stinging catfi sh are dangerous because and the Toxicological Centre consulted. In the pectoral fi ns of the connection between the stings in the pectoral fi n and of African catfi sh there are 8 rays, the fi rst of which are the venom cells [10, 11, 12]. In Asia, fi shermen are afraid much larger than the others (I 7); they are serrated and con- of this fi sh and if they catch it in their nets they remove nected with the shoulder girdle by an articulation. Three it with a piece of cut-off net with great care. The sting- well developed articulations allow the stings erection and ing catfi sh has become a popular aquarium fi sh in Poland locking when the catfi sh is disturbed (Fig. 1). The stings and is available in almost every pet shop. It is also bred on are responsible for most of the morbidity cases resulting a large scale. Cases of freshwater catfi sh H. fossilis and from catfi sh encounters. C. gariepinus stings envenomation are presented here. The toxicological centres in Poland have recorded 10 cases of envenomations caused by stinging catfi sh. The MATERIALS AND METHODS affected persons were aquarium fi sh breeders, and enven- omations occurred during tank tending and fi sh feeding. In the Clinic of Toxicology of the Jagiellonian University Injuries were puncture in all cases. The wounds were on Medical College, various patients are evaluated and hospi- the left hand in 2 victims, right hand in 8. The injury was talised due to bites infl icted by animals occurring naturally accompanied by intense pain, numbness of the site, dizzi- in Poland [9], as well as those bred in home aquariums ness, local oedema and erythema. In addition, symptoms [10]. Additionally, the Centre for Toxicological Informa- such as tachycardia, weakness, arterial hypotension, loss of tion of the Jagiellonian University Medical College records consciousness, respiratory distress and unusual sensations and documents cases of animal-induced envenomation in (tingling, pricking) were observed (5 cases). We consider southern Poland. Co-operation between toxicological cen- these envenomations as moderately serious accidents. The tres from other regions of the country enables the registra- fi rst aid treatment for stinging catfi sh stings was removal tion and analysis of all cases of poisonings that occur in of all foreign material and irrigating the site with what- Poland. Cases of catfi sh-induced envenomation were sub- ever clean liquid is available, warm water immersion and ject to analysis – 17 patients were injured by freshwater pain management. Radiographs aimed at the inspection for Catfi sh stings and the venom apparatus of the African catfi sh Clarias gariepinus, and stinging catfi sh Heteropneustes fossilis 165

lateral condyle

foramen lateral condyle lateral condyle lateral condyle

median condyle foramen median condyle

Figure 1. Pectoral sting of Clarias gariepinus. Figure 2. Pectoral sting of Heteropneustes fossilis. foreign bodies was used in all cases. The patients received the interval between the injury and the presentation, and a prophylactic short course of oral therapy with trimetho- the presence of a foreign body. As injuries infl icted by cat- prim-sulfamethoxazole. Tetanus prophylaxis was given fi sh may result in delayed presentation of infection, it was when indicated (7 cases). Some patients were observed for suggested that the patients should be admitted for observa- 24 hours (5 cases). In all cases, no residual defi cits in mo- tion [1, 2, 10]. In the case of injury infl icted by catfi sh, in- tor or sensory functions were noted. Over 2 months, the fection may develop even within 3 months of the incident; wounds healed slowly by second intention. Pectoral fi ns the patients were therefore instructed to have check-ups of stinging catfi sh possess 8 rays (I 7). The fi rst ray (spine) [1, 10]. It has been demonstrated that tissue extracts from is well-developed: serrated with a sharp end, it looks like stinging catfi sh and walking catfi sh Clarias batrachus (L) a harpoon. Three articulations allow erection and locking induced cardiotonic activity in isolated hearts of frogs, and (Fig. 2). the extracts from H. fossilis had a greater infl uence than those of C. batrachus. The epidermal secretions of stinging DISCUSSION catfi sh and walking catfi sh are rich in lipids and proteins while carbohydrates are very low. It has been shown that After catfi sh envenomation the following may occur: lipids are the principal constituents of the skin of these fi sh. persistent cutaneous oedema, erythema, intense burn- Most of the lipids are phospholipids [12]. The concentra- ing or throbbing pain that may appear at the wound site. tion of proteinaceous material secreting cells around the Paresthesias, weakness, localized sweating, and muscular pectoral sting has led to the evolution of the venom gland fi brillation can be accompanied by cyanosis and infl am- in catfi sh [3]. Rupture of this epithelium during enveno- mation around the puncture site. Lymphangitis, cellulitis, mation is the source of the venom injected into the vic- and septicaemia may be sequelae [1, 2, 6, 10, 11]. Other tim’s body. The severity of the envenomation depends on systemic symptoms may also be present, including tachy- the fi sh species, the number of stings, and the amount of cardia, hypotension, nausea and vomiting, dizziness, respi- venom released – the amount of venom is correlated with ratory distress, and loss of consciousness [1, 2, 6, 10, 11]. the size of the fi sh. The management of the envenomation Immersion of the injured part in 45°C water for at least caused by African catfi sh venom, noted in Poland, was 30–90 minutes may be benefi cial to relieve muscle spasms predominantly symptomatic. The aid was usually provided and intense pain; it may also inactivate some venom in the by fi rst-contact physicians and sometimes the Toxicologi- wound [1, 6, 10]. The use of parenteral analgesics may be cal Centre was consulted. In the case of stinging catfi sh necessary to control pain. Tetanus prophylaxis should be poisoning the treatment is mainly symptomatic [10, 11]. given when indicated. Antibiotic management depends on Although these injuries are intensely painful, most such several factors: the age and immune status of the victim, envenomations heal without sequelae. Occurrences of this 166 Satora L, Kuciel M, Gawlikowski T type of fi sh injury is therefore likely to become more com- develops following immediate penetration of Erysip- mon, and with freer movement of goods within the ECG, elothrix rhusiopathiae (Migula 1900, Buchaman 1918), more widespread. Every, even small, injury caused by Af- bacteria, the source of which are predominantly fi sh and rican and stinging catfi sh healed very slowly. The skin is a pigs. Erysipeloid is usually occupation-related – it occurs part of the non-specifi c immunological system protecting in fi shermen and fi sh traders, hence its English name ‘fi sh- the body against potential environmental pathogens. Fish handler’s disease’ [8]. After the period of incubation, which bites, stings and scratches facilitate the penetration of mi- usually takes several days, a very strong pain occurs with croorganisms across the skin into underlying tissues that oedema and circumscribed bluish-red skin lession. are susceptible to infection [4, 8]. Freshwater catfi sh gener- ally stay in slow, still, and often dirty waters, thereby po- CONCLUSIONS tentially increasing the risk of infection. Increased infl am- matory response and necrosis caused by fi sh venom may The envenomation caused by some species of exotic bring about extensive destruction of the integument as well freshwater catfi sh (C. garipepinus and H. fossilis) noted as dysfunction of the humoral and cell-mediated response, in Poland was usually moderate, the management was pre- which is conducive to infections caused by opportunistic dominantly symptomatic. microorganisms and physiological fl ora of the body. 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