Protective Effectiveness of an Immunization Protocol Against the Toxic Effects of Loxosceles intermedia Venom in Rabbits

Miranda, Ana Luísa Soares de; Lima, Sergio Monteiro; Botelho, Ana Flávia Machado; Campos, Marco Túlio Gomes; Eckstein, Camila; Minozzo, João Carlos; Chávez-Olortégui, Carlos; Soto-Blanco, Benito

doi:10.3389/fvets.2022.852917

Cited by 3 publications

(1 citation statement)

References 42 publications

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“…Antivenom remains the most suitable treatment for loxoscelism, a syndrome triggered by the bite from a brown spider (Loxosceles spp.) [1][2][3]. The most common manifestation of loxoscelism is cutaneous, and consists of a progressive dermonecrotic lesion with gravitational spreading.…”

Section: Introductionmentioning

confidence: 99%

The Health Status of Horses Used for at Least Six Complete Cycles of Loxoscelic Antivenom Production

Miranda,

Antunes,

Minozzo

et al. 2023

Toxins

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Antivenom production against Loxosceles venom relies on horses being immunized and bled for plasma harvest. One horse can partake in several cycles of antivenom production, which will require years of constant venom and adjuvant inoculation and bleeding. The actual impact on the health of horses that participate in several antivenom-producing cycles is unknown. Therefore, this study aimed to evaluate the general health status of horses that underwent at least six cycles of loxoscelic antivenom production. Seven crossbred horses that had partaken in six to eight complete antivenom-producing cycles were used and established as the immunized group (IG). Under the same handling and general management, eleven horses were established as the control group (CG). The horses were evaluated regarding their general clinical status and had their blood sampled, and an ECG recorded. The IG presented lower RBC and PCV, despite keeping values within inferior limits for the species. Renal function was not impaired, and liver-related enzymes were higher than those in the CG, probably due to liver exertion from immunoglobulin synthesis. ECG showed some abnormalities in the IG, such as atrioventricular block and a wandering atrial pacemaker, corroborated by an increase in CK-MB. The cardiovascular abnormalities were mainly found in the horses that participated in several antivenom-producing cycles. The overall results indicate that these horses had some impairment of their general health status. Once available, some alternative, less toxic antigens should replace the venom for immunization of horses used for antivenom production.

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Section: Introductionmentioning

confidence: 99%

The Health Status of Horses Used for at Least Six Complete Cycles of Loxoscelic Antivenom Production

Miranda,

Antunes,

Minozzo

et al. 2023

Toxins

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Envenomation by Brown Spider (Loxosceles sp.) in a German Shepherd Bitch - Laboratory and Anatomopathological Findings

Cristina Vann,

Waller,

Tavares Barwaldt

et al. 2024

Acta Scientiae Vet.

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Background: Although small in size, the brown recluse spider (Loxosceles sp.) often has the habit of hiding in intradomestic and dark places, causing accidents in humans and animals. Brown spiders are not aggressive, but bites occur when they are compressed, attacking quickly and leaving immediately, making difficult the spider recognition. The bite is usually painless or similar to a mosquito bite, hampering to perceive the accident, mainly for the owner of small animals. There is currently no antivenom available for veterinary use against arachnid bites, and the delay in suspicion and diagnosis of loxoscelism are usually fatal. This report aimed to describe a case of dermonecrotic lesions suspected of Loxosceles sp. bite in a young German Shepherd bitch. Case: A 6-month-old bitch German shepherd dog, weighing 27 kg, was admitted with a history of swelling in the right forelimb for over a week. Clinical examination revealed stupor, pale mucous membranes, and enlarged lymph nodes. Edematous hematomas on the forelimb, spreading widely over the ventral abdominal region were noted, including necrosis and a small double perforation (~0.3 cm) in the axillary region, like inoculation by spider chelicerae. Leukocytosis, elevated platelet aggregation, and high fibrinogen led to the suspicion of a brown spider bite. Uremia, hypoalbuminemia, and elevated alkaline phosphatase, together with urinalysis (intense proteinuria and occult blood) indicated acute kidney failure. The radiography showed soft tissue enlargement in the right forelimb. Ultrasonography revealed liver condition and splenomegaly. Despite administering emergency supportive care, the patient died 12 h after admission. Necropsy revealed necrotic dermatitis and necrohemorrhagic myositis, renal (acute toxic tubular) and hepatic necrosis, pulmonary edema, splenic congestion, myocardial infarction, and stroke, showing critical systematic alterations compatible with the myonecrotic and hemorrhagic action of the brown spider venom. Although the spider was never found, this case reinforces the prompt treatment and thorough clinical inspection for the accurate diagnosis of loxoscelism. Discussion: The bitch presented the viscerocutaneous form of loxoscelism, there is an aggressive and fatal presentations, with necrotic areas in the forelimb and ventral abdomen, besides leukocytosis, platelet aggregation, thrombocytopenia, proteinuria, and occult blood in urine. Considering that the swelling in the forelimb was noticed by the owner for more than a week and that the dog was belatedly taken to the veterinary hospital, its clinical condition has worsened, compromising the systemic organs. Loxosceles sp. venom inactivate the serum hemolytic complement, inducing rapid coagulation and occlusion of small capillaries, and subsequent tissue necrosis. Necrotic signs are mainly caused by proteins belonging to the phospholipase D family ("dermonecrotic toxins"), which are also responsible for hemolysis, thrombocytopenia, and renal failure. Due to the delay in obtaining veterinary intervention since the history and the systemic complications, the animal died. The necropsy showed intense necrosis at the muscular level and in systemic organs, as noted in the right forelimb, kidneys, liver, brain, and heart. The pathological findings were compatible with accidents with poisonous animals in which their toxins have myonecrotic and hemorrhagic action. Together with the presence of small double perforation in the forelimb, suggestive of inoculation by spider chelicerae, the clinical diagnosis was concluded. Although the spider was never found, this case reinforces the prompt treatment and thorough clinical inspection for the accurate diagnosis of loxoscelism. Keywords: brown spider, Loxosceles spp., loxoscelism, dog, poisoning, toxicology.

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Clinical Effects of the Immunization Protocol Using Loxosceles Venom in Naïve Horses

Miranda

Antunes²,

Minozzo³

et al. 2022

Toxins

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Bites of brown spiders (Loxosceles spp.) are responsible for dermonecrotic lesions and potentially systemic envenoming that can lead to death. The only effective therapy is the use of the antivenom, usually produced in horses. However, little is known about the consequences of the systematic use of the Loxosceles venom and adjuvants and of the bleedings on antivenom-producing horses. Thus, the aim of this study was to evaluate the clinical changes in horses in their first immunization protocol for Loxosceles antivenom production. Eleven healthy horses, never immunized, were evaluated in three different periods: T0 (before immunization); T1 (after their first venom immunization); and T2 (after their first bleeding). Horses were clinically evaluated, sampled for blood, and underwent electrocardiographic (ECG) recordings. Several suppurated subcutaneous abscesses occurred due to the use of Freund’s adjuvants and thrombophlebitis due to systematic venipunctures for the bleeding procedures. ECG showed arrhythmias in few horses in T2, such as an increase in T and R waves. In summary, the immunization protocol impacted on horses’ health, especially after bleeding for antivenom procurement.

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Protective Effectiveness of an Immunization Protocol Against the Toxic Effects of Loxosceles intermedia Venom in Rabbits

Cited by 3 publications

References 42 publications

The Health Status of Horses Used for at Least Six Complete Cycles of Loxoscelic Antivenom Production

The Health Status of Horses Used for at Least Six Complete Cycles of Loxoscelic Antivenom Production

Envenomation by Brown Spider (Loxosceles sp.) in a German Shepherd Bitch - Laboratory and Anatomopathological Findings

Clinical Effects of the Immunization Protocol Using Loxosceles Venom in Naïve Horses

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