Menace of acaricide resistance in cattle tick, Rhipicephalus microplus in India: Status and possible mitigation strategies

Highlights

• Overall status of acaricide resistance in Indian cattle ticks was analysed.

• Multi-acaricide resistance population is creating problem in tick management programme.

• Region specific integrated management strategies are recommended for maintaining production.

Abstract

Livestock in general and dairy sector in particular plays a vital role in the Indian economy and in the socio-economic development of millions of people. Rhipicephalus microplus, a one-host and the most prevalent cattle tick in various agro climatic zones of India. This tick species is responsible for severe economic losses to livestock owners both through the direct effects of blood sucking, injection of toxins and indirectly by transmitting pathogens. Due to inadvertent and indiscriminate use of chemicals to kill ticks, field tick population has developed resistance to almost all chemicals that are used to manage them. The intention of this review is to provide the current status of resistance in ticks, the possible mechanisms of resistance operating in the tick population, factors contributing to the development of resistance and the managemental strategies.

Introduction

India is predominantly an agriculture dominated country. It is home to the world’s largest bovine population of 299.9 million which includes 190.90 million cattle and 108.7 million buffaloes (DAHD, 2015) accounting for 16.2 and 56.9 %, respectively, of the world bovine population. Despite very low productivity per animal, India stands first in the world milk production accounting for 20 % of world output (DAHD, 2018). The livestock sector is significantly contributing to the Indian economy by providing milk, meat, bones and hides. Apart from this, livestock plays a major role in maintaining soil fertility, energy production and rural transportation. The overall contribution of the livestock sector in total GDP is nearly 4.11 % at current prices during 2012–13 (DAHD, 2015). However, this sector is sufferings from many health related problems posed by bacteria, viruses, fungi, and parasites (both endo and ectoparasites). Of the different problems, management of the multidimensional problems created by tick infestations is very challenging. Due to ideal environmental conditions, almost all the economically important livestock species are suffering from ticks and tick-borne diseases (TTBDs) (Ghosh et al., 2007). In a questionnaire survey, the control cost of TTBDs in India has been estimated at the tune of 498.7 million US$/annum (Minjauw and McLeod, 2003).

In India, the problem of TTBDs is particularly relevant because of large-scale maintenance of susceptible crossbred animals to improve and sustain the production of milk and milk products. Despite efforts have been made to develop other non-chemical methods to manage ticks, the use of chemical acaricides is still a predominant approach implemented in the field (Ghosh and Nagar, 2014). Amongst 106 valid tick species reported from India, R. microplus is widely prevalent and is the most damaging species infesting livestock, zoo and wild animals (Ghosh et al., 2007). Due to short and single host life cycle with high fecundity, the R. microplus has been subjected to maximum exposure of acaricides and thus developed a remarkable ability to become resistant to the toxic effect of the chemicals used to manage them. Globally, R. microplus has become resistant to almost all the classes of chemicals that are registered for use against it, for example; against organophosphates and carbamates (Li et al., 2005; Kumar et al., 2011); pyrethroids (Ghosh et al., 2015; Klafke et al., 2017a); amidines (Miller et al., 2002; Klafke et al., 2017b); macrocyclic lactones (Martins and Furlong, 2001; Perez-Cogollo et al., 2010a; Klafke et al., 2017a; Nandi et al., 2018); fipronil (Castro-Janer et al., 2010; Klafke et al., 2017a) and against fluazuron (Reck et al., 2014).

The tick management programme is focused on repeated use of organophosphates, pyrethroids, formamidines and macrocyclic lactones. Uses of formamidines (amitraz) and macrocyclic lactones (ivermectin) are comparatively less but on the rise due to the declining efficiency of organophosphates and pyrethroids acaricide. By a questionnaires survey in sampled population, FAO (2004) predicted the establishment of widespread acaricidal resistance tick populations in India. Later, with the establishment of country specific discriminating concentration (DC) of commonly used acaricides, the reports of resistance and the possible mechanism of development of acaricidal resistance in R. microplus against various types of acaricide are published from different parts of the country (Singh et al., 2010; Kumar et al., 2011; Sharma et al., 2012; Kumar et al., 2013; Jyothimol et al., 2014; Kumar et al., 2014; Singh et al., 2015a; Kumar et al., 2017; Nagar et al., 2018; Sharma et al., 2018; Godara et al., 2019) (Table 3).

The purpose of this review is to appraise the overall acaricide resistance scenario and to provide an overview of the current state of knowledge, research gaps, present and future national initiatives required to combat the menace of the complex problem.