Passage: Most people with dengue recover without any ongoing problems. The fatality rate is 1–5%, and less than 1% with adequate treatment; however those who develop significantly low blood pressure may have a fatality rate of up to 26%. Dengue is common in more than 110 countries. In 2013 it causes about 60 million symptomatic infections worldwide, with 18% admitted to hospital and about 13,600 deaths. The worldwide cost of dengue case is estimated US$9 billion. For the decade of the 2000s, 12 countries in Southeast Asia were estimated to have about 3 million infections and 6,000 deaths annually. It is reported in at least 22 countries in Africa; but is likely present in all of them with 20% of the population at risk. This makes it one of the most common vector-borne diseases worldwide.Infections are most commonly acquired in the urban environment. In recent decades, the expansion of villages, towns and cities in the areas in which it is common, and the increased mobility of people has increased the number of epidemics and circulating viruses. Dengue fever, which was once confined to Southeast Asia, has now spread to Southern China, countries in the Pacific Ocean and America, and might pose a threat to Europe.Rates of dengue increased 30 fold between 1960 and 2010. This increase is believed to be due to a combination of urbanization, population growth, increased international travel, and global warming. The geographical distribution is around the equator. Of the 2.5 billion people living in areas where it is common 70% are from Asia and the Pacific. An infection with dengue is second only to malaria as a diagnosed cause of fever among travelers returning from the developing world. It is the most common viral disease transmitted by arthropods, and has a disease burden estimated at 1,600 disability-adjusted life years per million population. The World Health Organization counts dengue as one of seventeen neglected tropical diseases.Like most arboviruses, dengue virus is maintained in nature in cycles that involve...

Question: What is believed to have caused an increase in the rate of dengue cases, which is more broadly referred to as climate change?
urbanization, population growth, increased international travel, and global warming