loxoscelism, spider bite, Loxosceles laeta, Loxosceles intermedia, epidemiology, pathology, Brazil. Introduction. Loxoscelism is a necrotizing-haemolytic.
TRANSACTIONS OFTHE ROYALSOCIETY OFTROPICAL MEDICINE AND HYGIENE (1998)92,546-548
A clinical Catarina,
and epidemiological Brazil
study of Loxosceles
spider envenoming
in Santa
Ulisses Marlon Sezerinol, Marlene Zanninl, Luciano Kowlaski Coelhol, Jo50 Gonplves, jrl, Margareth Grandol, Suely Grossemann Mattosinhol, Jofio Luiz Costa Cardosoz, Vera Regina von Eickstedtz, Francisco Oscar Siqueira FranGa2, titia Cristina Barbaro2 and Hui Wen Fan2 ICentro de Informa@es Toxicolbgicas, Hospital
Universitcirio,
UFSC,
Florianbpolis,
SC, Brazil;2Instituto
Butantan,
SEo Paulo,
Se Brazil
Abstract A clinical and epidemiological study of 267 cases of envenomation by Loxosceles spp. (loxoscelism), notified to Centro de Informaqdes Toxicol6gicas de Florian6polis (Santa Catarina State, Brazil), was conducted between January 1985 and December 1995. Most of the incidents occurred along the coast of the mid-southern region of the state, during the warmest months. L. Zaeta and L. intermedia were identified as the causative agents. Cutaneous loxoscelism was clinically diagnosed in 232 (86.9%) patients with local pain (86.5%), oedema (80.5%), hyperaemia (79.8%) and necrosis (56.9%). Cutaneous-visceral loxoscelism was detected in 35 patients (13.1%) with intravascular haemolysis, manifested by jaundice (68.6%), oliguria (45.7%), dark urine (28.6%), haemorrhage (25.7%), anuria (8.6%) and shock (2.9%), besides the cutaneous effects. Specific antivenom was given to 125 patients (46.8%) and only 8(6.5%) had mild reactions. Acute renal failure was observed in 17 cases (6.4%); 4 patients (1.5%) died, all of whom were children under 14 years old. Keywords:
loxoscelism, spider bite, Loxosceles laeta, Loxosceles intermedia,
Introduction Loxoscelism is a necrotizing-haemolytic syndrome caused by spiders of the genus Loxosceles (Scytodidae) and human envenomation has been reported in diverse regions of the world (MARTINEZ-VARGAS,1987; REES et&
1987; CARDO~Oet
al.,
1988; SCHENONEet
al.,
1989: BORKANet al.. 1995). Ponularlv known as brown spiders, Loxosceles sip. va& in ieng& from 1 to 5 cm, live in rural and urban environments, and can be found indoors in dark areas such as storage closets and basements (GERTSCH,1967). The spidersare not aggressive and are often overlooked. In Brazil, 7 species have been reported, most of them in the south and south-east regions (EICKSTEDT, 1994), and bites usually occur when sleeping people roll on to an unnoticed spider. No other spider has been implicated in the necrotizing-haemolytic syndrome. The precise pathophysiology of loxoscelism has not been elucidated. The cutaneous and visceral effects are probably due to a multifactorial process involving direct tissue damage, secondary vascular injury and release of enzymes by polymorphonuclear cells. Sphingomyelinase D seems to be the most important component present in the venom, and it is considered to be the cause of the necrotic skin lesion, haemolysis and platelet aggregation (FUTRELL,1992). Since 1986, the incidence of loxoscelism has increased in sou&ern Brazil (RIBEIROet al., 1993). Loxoscelism was resuonsible for 36% of the 17781 snider bites notified td the Ministry of Health between i990 and 1993 (BRAZIL, in press).This fact highlighted the importance of loxoscelism as an important public health problem and little is known about its epidemiology. The objective of this study was to investigate clinical and epidemiological aspects of envenomation caused by Loxosceles spp. in Santa Catarina State, Brazil. Patients and Methods A retrospective study of Loxosceles bites notified to Centro de Informacdes Toxicol6aicas (CIT) de Florianbpolis, Santa Catarina State, Brazil &as carried out between Tanuarv 1985 and December 1995. Selection of cases “was based on identification of the offending agent, or a history of spider bite and presence of suggestive clinical manifestations of Loxosceles envenomation.
epidemiology, pathology, Brazil
Cutaneous loxoscelism (CL) was defined as a mildly painful blister or papulovesicular lesion that evolves with a marked increase in swelling and tenderness into a haemorrhagic and grey-blue macule, indicating cutaneous ischaemia, within 12-48 h after the bite. Subsequently, the central portion becomes necrotic and sloughs, producing a deep, sharply defined ulcer, and the sloughed area takes weeks or months to heal. Cutaneous-visceral loxoscelism (CVL) was defined as a sum of compatible symptomatology of intravascular haemolysis, whether the local reaction wastypical or not. A standardized proforma was used to collect clinical and epidemiological data, including characteristics of the patient (sex, age, location of bite, interval between bite and hospital admission), circumstances of the bite, identification of the agent (if available), symptoms at hospital admission, progression of the cutaneous lesion and systemic effects, treatment (including antivenom therapy), and outcome. Specific Loxosceles antivenom or polyvalent (Loxosceles, Phoneutria, Tityus) antivenom,
produced by Instituto Butantan, SPoPaulo and distribbted free to-the referral hospitals, was administered following Ministrv of Health rmidelines (BRAZIL,in mess). Spivders we& captured& the paGents’ h&s anh neighbourhoods in different regions of Santa Catarina State and identified by technical staff. In order to study the frequency distribution of variables, a database was constructed using the software EpiInfo 6.02. Results Of the 487 suspect cases, 267 (54.8%) fulfilled the criteria for inclusion in the study. Only 2.6% of the patients brought the spider responsible for the bite. One 40 35 30 .g 25 P 5 20 2
15 10 5 n
Address for correspondence: Marlene Zannin, Centro de Informa+esToxicoldgicas de Santa Catarina, Hospital Universitario, UFSC, CEP. 88.040-900, Florian6polis, Santa Catarina, Brazil; fax +55 48 234 1016.
Jan.
Feb.
Mar.
Apr.
May
Jun.
Jul.
Aug.
Sep.
Oct.
Nov.
Dec.
Figure. Seasonal variation of incidence of bites by Loxosceles spp. in Santa Catarina? Brazil; January 1985 to December 1995. [Data for one patient were not recorded.]
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LOXOSCELES
SPIDERENVENOMING
547
hundred and seventy-eight bites (66.7%) occurred during the warmest months, October-March (Figure), and 215 (80.5%) took place in the coastal region of the state. Bites occurred either in the day or at night, most of them indoors: 21.7% of the patients were dressing (generally the spider was within the clothes), 17.2% were sleeping, and 15.4% were performing other activities inside the house. The mean age of patients was 25.1 years (SD=l8.9) and most of them (59.9%) were between 15 and 59 years old; 33.0% were under 14 years old, and 6.0% were aged 60 years or more (the age of 1.1% was not known). Women were slightly more often bitten than men (57.3%). The time elapsed between bite and hospital admission was 12 h or less in only 23 cases (8.6%); 119 (44.6%) sought medical assistance after 1348 h, and 97 (36.3%) after 48 h; this information was not available for 28 patients (10.5%). Although the most frequent bitten areas were the lower (45.4%) and upper (29.9%) limbs, a significant proportion of patients was not bitten on the extremities (Table 1). Table 1. Anatomical location of bites by Loxosceles spp. in 267 patients Location
No. of bites
Foot
41(15.4%) 40(15.o%j 40(15.0%) 4 (1.5%) 30(11.2%) 26 (9.7%) 24 (9.0%) 30(11.3%) 5 (1.9%) 5 (1.9%) 13 (4.9%) 9 (3.4%)
Leg
Thigh Buttock Hand Forearm Arm Trunk Abdomen Genitals Head/neck Not known Table 2. Local signs and symptoms bite by Loxosceles spp. Symptom
or sign
Pain Oedema Hmeraemia Nkcrosis Blistering Ecchym&is Secondary infection Ischaemia Pruritus Other
in 267 cases of Frequency 231(86.5%) 215(80.5%) 213 (79.8%) 152(56.9%) 131(49.1%) i 13 (42.3%j 49 (18.4%) 28(10+%) 21 (7.9%) 15 (5.6%)
After excluding the possibilities of other dermatological conditions, such as skin infection and herpes, CL was diagnosed in 232 patients (86.9%) and CVL in 35 (13.1%). Local signs and symptoms are detailed in Table 2. In addition to the cutaneous lesions, patients with CVL presented jaundice (68.6%), oliguria (45.7%), dark urine (28.6%), haemorrhage (25.7%), anuria (8.6%) and‘ shock- (2.9%). Then.&-two -patients (62.9%) with CVL were children under 14 vears old: 22
