Heartworm and Wolbachia: Therapeutic implications

Establishment of macrocyclic lactone resistant Dirofilaria immitis isolates in experimentally infected laboratory dogs

“…Some practices in high prevalence areas had over 50 cases per year, some reported resistance in up to 25% of dogs under their care, and 74% of practices indicated they had seen at least one LOE case in the past year. Faced with the uncertainty presented by apparent frequent drug failure, especially in large breed outside dogs subjected to bites from large mosquito populations, practices in some areas abandoned the commonly used monthly preventive drugs and began searching for alternative preventive protocols, including use of monthly preventive drugs administered at higher doses, long-acting injectable or topical ML drugs that maintain high continuous blood levels [8], or strategic use of doxycycline in combination with ML drugs [15][16][17]. Some of the long-acting ML drugs have additional label claims of efficacy against other helminthes in which ML is given at elevated doses above that needed for HW prevention alone [9].…”

Recent Advances in the Use of Anthelmintics for Treating Nematode Infections

“…림프관 사상충증과 회선사상충증 No chemotherapy is needed for human drofilariasis [55] For dogs, ivermectin (6 µg/kg/wk x 36)+ doxycycline (10 mg/kg intermittently for x 20 wks)+ melarsomine (2.5 mg/kg, 3 injectionse) satisfactory [60] a In addition to these drugs, doxycycline (200 mg/day for 21 days) should be given to kill Wolbachia bacterial endosymbionts [51]. For onchocerciasis, doxycycline (100-200 mg/kg for 42 days) can sterilize the female worms and lead to the absence of skin microfilariae [51] …”

Dirofilaria immitis and Wolbachia pipientis: a thorough investigation of the symbiosis responsible for canine heartworm disease

“…The only Food and Drug Administration-approved heartworm adulticidal drug used today is melarsomine dihydrochloride, which is administered intramuscularly in one of two dosage patterns (McCall et al 2008). First, a veterinarian can inject a dose of 2.5 mg per kg of body weight twice within 24 h and repeat the procedure 4 months later.…”

“…Severe inflammatory response of vascular tissue has also been observed after intensive adulticidal therapy, perhaps due to the release of Wolbachia from the bodies of the dead worms (McCall et al 2008). For this reason, the antibiotic doxycycline can be used in conjunction with or instead of melarsomine to kill the adult worms.…”