Human infections with neglected vector-borne pathogens in China: A systematic review

Abstract

Background: Emerging vector-borne pathogens (VBPs) pose a continuous background threat to the global health. Knowledge of the occurrence, distributions and epidemiological characteristics of VBP are lacking in many countries. Outbreaks of novel VBP are of increasing global interest including those arising in China.

Methods: A systematic review of published literature was undertaken to characterize the spectrum of VBPs causing human illness in China. We searched five databases for VBP-related articles in English and Chinese published between January 1980 and June 2021, that excluded those listed in the National Notifiable Diseases Surveillance System of China. The study is registered with PROSPERO, CRD42021259540.

Findings: A total of 906 articles meeting the selection criteria were included in this study. A total of 44,809 human infections with 82 species of VBPs including 40 viruses, 33 bacteria (20 Rickettsiales bacteria, eight Spirochaetales bacteria, and five other bacteria) and nine parasites, were identified in China. Rickettsiales bacteria were the most common and widely distributed pathogens with 18,042 cases reported in 33 provinces by 347 reviewed articles, followed by Spirochaetales bacteria with 15,745 cases in 32 provinces (299 articles), viruses with 8455 cases in 30 provinces (139 articles), other bacteria with 2053 cases in 19 provinces (65 articles), parasites with 514 cases in 17 provinces (44 articles), and multiple pathogens with 3626 cases in 14 provinces (23 articles). Coxiella burnetii, Bartonella henselae and Rickettsia sibirica were the most frequently reported pathogens. A total of 18 new pathogens were reported in China during this period (these also represented their first identification globally). Based on 419 articles with clinical information, a meta-analysis revealed that flu-like illness was the most common manifestation among infections with VBPs.

Interpretation: This review helps improve the understanding of VBPs in China, demonstrating the need to consider a wider surveillance of VBPs in many different settings, thus helping to inform future research and surveillance efforts.

Funding: Natural Science Foundation of China.

Figure 1

PRISMA flow chart of article assessed for the review (A), and timelines of published articles (B) on neglected vector-borne pathogens in human infection in China. (A) Flowchart outlining the protocol adopted in this systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA); (B) The bars fill in the blank and marked with “*” represent the article published in 2021.

Figure 2

Number of articles for each pathogen within each province in China from 1980 to 2021. In the Bubble diagram, the size of the circle represents the number of articles for each pathogen detected in each province. In the Cleveland dot chart, total count of articles of each pathogen were represented by using logarithmic converted length.

Figure 3

Distribution of extracted records of VBP causing human infection in China from 1980 to 2021 (A), and the first identification site of 75 VBPs causing human infection in China from 1980 to 2021 (B). (A) Records number of extracted literatures in seven ecological regions. Within each ecological region, the bar diagram was used to illustrate the published article number by decade, and the total number was reflected by the background color. The bars fill in the blank and marked with “*” represent the article published in 2020s. Ⅰ= Northeast region (NE), Ⅱ=North China region (N), Ⅲ=Inner Mongolia-Xinjiang region (IMX), Ⅳ= Qinghai-Tibet region (QT), Ⅴ=Southwest region (SW), Ⅵ=Central China region (C) and Ⅶ=South China region (S); (B) The location where the pathogen was firstly identified in human population is determined at prefecture level as referred to the included literatures. The number of tested positive of each pathogen were extracted from the dataset. The abbreviation of each pathogen was shown in Table 2.

Figure 4

Clustered Heat chart describing the weighed clinical presentations of each pathogen (A), and Radar chart illustrating the seven common clinical presentations by etiology (B). (A) The clinical presentations were divided into: (a) flu-like presentations (fever, headache, dizziness, cough, fatigue, and chills), (b) gastrointestinal presentations (nausea, vomit, diarrhea, and jaundice), (c) motor presentations (myalgia and arthralgia), (d) dermatologic presentations (rash, eschar, erythema), (e) neurological presentations (meningeal irritation, facioplegia and epilepsy), (f) lymphaenopathy, (g) hemorrhage. Six clusters were obtained according to the complete cluster analysis of clinical presentations; (B) Seven clinical presentations: fever, headache, dizziness, fatigue, chills, rash, and myalgia.