Biology subjects

Massei, G.

Publications and source records attributed to Massei, G..

2 recordsLinked to original sources

bioRxiv2025

Immune response to co-administration of bovine tuberculosis and contraceptive vaccines in badgers (Meles meles)

Controlling bovine tuberculosis (bTB) in livestock is often hindered by the presence of a wildlife reservoir, such as the Eurasian badger in the UK and Ireland. Vaccinating badgers against bTB can reduce the severity of Mycobacterium bovis infection and potential onwards transmission to cattle, badgers and other species, thus combined with population control might provide additional benefits (and reference models). To evaluate the effects of co-administration of a bTB vaccine (BCG) and a contraceptive vaccine (GonaCon), captive badgers were injected intramuscularly with either BCG only, GonaCon only or BCG+GonaCon (phase 1). The duration of immune response to BCG vaccination and booster vaccination was also evaluated in the BCG only group over a 24-month period (phase 2). The cellular immune responses to purified protein derivatives PPDA and PPDB, used to measure the effects of BCG, did not differ significantly between the BCG only and BCG+GonaCon badgers but were significantly different between the BCG only and GonaCon only badgers. Anti-GnRH antibody titres, quantified to measure the effect of GonaCon, peaked at the first sampling point for the majority of badgers in the GonaCon only and BCG+GonaCon groups. Throughout phase 1, lasting three months post-vaccination, badgers in both GonaCon treatment groups maintained high anti-GnRH antibody titres (1:128,000 or above) that are associated with infertility in this species, with no significant difference between the two GonaCon groups. The immune responses to BCG vaccination in the BCG only badgers (phase 2) were elevated at the first sampling point, approximately three weeks after initial vaccination and booster vaccination, generally declining thereafter. The results from the current study suggest that co-administration of BCG and GonaCon do not have notable deleterious effects on either of the vaccines and that the protective effect of BCG is enhanced by booster vaccination. The protective effects afforded by both vaccines when given together, in terms of reduced disease burden or fecundity, should be determined by further studies.

immunology↗

bioRxiv2018

Disease transmission mode has little effect on simulated canine rabies elimination

Disease transmission in animal populations can be affected by density or by frequency of contacts between individuals, although many models assume linear density-dependent transmission. We used rabies and free-roaming dogs (Canis familiaris) in two Nepalese cities as a model system to explore the impact of linear and non-linear density-dependent disease transmission on disease elimination achieved through rabies vaccination or vaccination and sterilisation. Strongly non-linear transmission approximated realistic frequency dependent transmission. Free roaming dogs, abundant in many parts of the developing world, are responsible for most cases of rabies transmission to humans. Most models of rabies transmission assume that the disease transmission rate is linearly density-dependent, although a recent empirical study did not find evidence to support this assumption. Rabies vaccination, culling and dog sterilisation are employed to eliminate rabies or to reduce the numbers of human cases. We created a continuous-time deterministic compartmental model to describe rabies epidemiology within a dog population and to analyse the two modes of transmission. Under each transmission mode, we investigated the efficacy of dog vaccination and fertility control to eliminate rabies. To investigate the effect of dog density on disease control efforts, models were run for cities with high and low dog population densities using data from the Nepalese cities. The results showed that, at low population density, the amount of control effort required for disease elimination did not differ substantially between different transmission modes. At high population density, the effort required to achieve disease elimination was only higher for linear density-dependent than for non-linear transmission due to the exact value of the transmission rate, beta. The model suggests that although disease transmission mode may alter the impact of control on rabies elimination, this impact is relatively small and probably not relevant to disease management.

ecology↗