Biology subjects

Meli, M. L.

Publications and source records attributed to Meli, M. L..

2 recordsLinked to original sources

bioRxiv2025

First detection of Cytauxzoon spp. DNA in questing Ixodes ricinus nymphs

Feline cytauxzoonosis is an emerging tick-borne disease in Europe. While infections have been reported in different European countries, the tick vector remains unknown. This study investigated 665 ticks collected in 2019 (n= 160), 2022 (n= 7) and 2024 (n= 658) in a Cytauxzoon spp. hotspot region in central Switzerland (62 ticks from cats; 603 ticks from vegetation). Ticks were morphologically characterized, pooled by origin and life-stage, screened for Cytauxzoon spp. 18S rRNA by qPCR and conventional PCR and positive samples confirmed by sequencing. All ticks belonged to Ixodes ricinus (50 males, 83 females, 532 nymphs). Four tick pools from 2019 tested Cytauxzoon spp. positive: one pool of 4 non-engorged male ticks from cats and three pools of 5-6 nymphs each from vegetation. All ticks collected in 2022 and 2024 tested negative. Amplification of the almost full-length (1535 bp, 1 pool) or partial (219-140 bp, 3 pools) 18S rRNA gene revealed a sequence identify of 98.6-100% with Cytauxzoon spp. previously detected in cats from this area. The detection of Cytauxzoon spp. in questing Ixodes ricinus nymphs suggests a potential role of this tick species in the parasites transmission cycle in Central Europe and raises the possibility of transovarial transmission. Mitochondrial gene sequencing was unsuccessful, but the detected Cytauxzoon spp. likely represent Cytauxzoon europaeus. Discrepancies between qPCR and conventional PCR results point to possible amplification of tick endosymbionts, highlighting the importance of confirmatory sequencing particularly when testing tick-derived DNA. In conclusion, this is the first report of Cytauxzoon spp. in questing I. ricinus ticks in Europe. Our findings underscore the need for further research to confirm vector competence and clarify transmission dynamics.

microbiology↗

bioRxiv2025

Navigating Neurological Re-emergence in Feline Infectious Peritonitis: Challenges and Insights from GS-441524 and Remdesivir Treatment

Case summaryA six-month-old male British Longhair cat presented with acute neurological signs, ocular changes, massive ascites and laboratory parameters consistent with feline infectious peritonitis (FIP). Systemic and neurological signs fully resolved with initial treatment (GS-441524 [BOVA UK, 15 mg/kg PO q24h, 42 days], levetiracetam [20 mg/kg q8h] and prednisolone [1 mg/kg q24h until Day 21 = D-21]). Lethargy and fever reappeared seventeen days after treatment. Four days later, severe multifocal neurological signs reemerged. High-field MRI revealed multifocal intra-axial and intramedullary lesions in the brainstem and cervical spinal cord, severe meningitis and generalised mild ventriculomegaly. Feline coronavirus (FCoV) RNA was detected in the cerebrospinal fluid by RT-qPCR. Abdominal effusion was absent. Serum alpha-1-acid glycoprotein (AGP) was again elevated. FIP re-emergence was suspected, and antiviral treatment was resumed. After one day of GS-441524 treatment (15 mg/kg PO q24h), severe hypoventilation developed, requiring intubation and mechanical ventilation for 1.5 days. Treatment was switched to remdesivir (Veklury, Gilead, 16.7 mg/kg IV q24h) for four days. Oral GS-441524 was then reintroduced (10 mg/kg q12h) and continued until D-84. Treatment resulted in partial recovery with moderate ataxia and reduced left-sided menace response remaining 181 days after starting the second treatment. Relevance and novel informationThis case illustrates the complexity of diagnosing and treating re-emerging FIP-associated neurological signs. AGP monitoring offers a promising noninvasive approach for early detection of relapse. By adapting short- and long-term antiviral treatment and providing intensive care, excellent long-term outcomes can be obtained for cats with severe relapsing FIP-related neurological signs.

microbiology↗