Babesiosis as a potential threat for bovine production in China

Lan He,Lan He,Guohua Hua,Junlong Zhao,Carlos E Suarez,Carlos E Suarez,Guiquan Guan,Guiquan Guan,Yali Sun,Reginaldo G Bastos

doi:10.1186/s13071-021-04948-3

Abstract

Babesiosis is a tick-borne disease with global impact caused by parasites of the phylum Apicomplexa, genus Babesia. Typically, acute bovine babesiosis (BB) is characterized by fever, anemia, hemoglobinuria, and high mortality. Surviving animals remain persistently infected and become reservoirs for parasite transmission. Bovids in China can be infected by one or more Babesia species endemic to the country, including B. bovis, B. bigemina, B. orientalis, B. ovata, B. major, B. motasi, B. U sp. Kashi and B. venatorum. The latter may pose a zoonotic risk. Occurrence of this wide diversity of Babesia species in China may be due to a combination of favorable ecological factors, such as the presence of multiple tick vectors, including Rhipicephalus and Hyalomma, the coexistence of susceptible bovid species, such as domestic cattle, yaks, and water buffalo, and the lack of efficient measures of tick control. BB is currently widespread in several regions of the country and a limiting factor for cattle production. While some areas appear to have enzootic stability, others have considerable cattle mortality. Research is needed to devise solutions to the challenges posed by uncontrolled BB. Critical research gaps include risk assessment for cattle residing in endemic areas, understanding factors involved in endemic stability, evaluation of parasite diversity and pathogenicity of regional Babesia species, and estimation of whether and how BB should be controlled in China. Research should allow the design of comprehensive interventions to improve cattle production, diminish the risk of human infections, and increase the availability of affordable animal protein for human consumption in China and worldwide. In this review, we describe the current state of BB with reference to the diversity of hosts, vectors, and parasite species in China. We also discuss the unique risks and knowledge gaps that should be taken into consideration for future Babesia research and control strategies.

Highlights

Babesiosis is a public health threat to human, domestic, and wild animals worldwide, especially in tropical and subtropical regions
Recent phylogenetic analysis of 18S rRNA gene and internal transcribed spacer region demonstrated that B. ovata Lushi, B. ovata Ningxian, B. ovata (Wenchuan isolate), and B. ovata Zhangjiachuan, which are all transmitted by H. longicornis, fall into one single clade, while B. major (Yili isolate), which is transmitted by H. punctata, falls into a separate clade [34, 41]
There is still much to be learned on parasite diversity and the dynamics of the disease in the country before methods of control can be applied effectively

Summary

Background

Babesiosis is a public health threat to human, domestic, and wild animals worldwide, especially in tropical and subtropical regions. Recent phylogenetic analysis of 18S rRNA gene and internal transcribed spacer region demonstrated that B. ovata Lushi, B. ovata Ningxian, B. ovata (Wenchuan isolate), and B. ovata Zhangjiachuan, which are all transmitted by H. longicornis, fall into one single clade, while B. major (Yili isolate), which is transmitted by H. punctata, falls into a separate clade [34, 41] Both these Babesia species have low pathogenicity in intact calves, do not cause apparent clinical disease, and are not generally considered important pathogens, in comparison to B. bovis and B. bigemina [30, 31, 40]. It is interesting that some parasite species that are known to infect certain hosts, such as B. motasi, a parasite that causes disease in sheep, were only identified infecting cattle in China [11] This situation differs dramatically from other endemic countries, such as Australia, Brazil, Mexico, and Argentina, among other countries, where the diversity of Babesia spp. appears to be much more limited and usually restricted only to B. bovis and B. bigemina [67–70]

Conclusions

Findings

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