A patient suffering from dengue fever chats with a woman while sitting under a mosquito net inside a dengue and malaria ward at the Sindh Government Services Hospital in Karachi, Pakistan September 21, 2022. REUTERS/Akhtar Soomro 

A patient suffering from dengue fever sits under a mosquito net inside a dengue and malaria ward at the Sindh Government Services Hospital in Karachi, Pakistan September 21, 2022. REUTERS/Akhtar Soomro 

A dengue fever patient lies under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, September 16, 2022. REUTERS/Fayaz Aziz 

A dengue fever patient lies under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, September 16, 2022. REUTERS/Fayaz Aziz 

Sagrario Ponce sits with her son Yafer who is suffering symptoms of dengue fever at Hospital Escuela, as authorities reported a nationwide fever outbreak, in Tegucigalpa, Honduras June 24, 2022. REUTERS/Fredy Rodriguez 

Dylan Santiago Sierra lies on a hospital bed while suffering symptoms of dengue fever at Hospital Escuela, as authorities reported a nationwide fever outbreak, in Tegucigalpa, Honduras June 24, 2022. REUTERS/Fredy Rodriguez 

Sagrario Ponce sits with her son Yafer who is suffering symptoms of dengue fever at Hospital Escuela, as authorities reported a nationwide fever outbreak, in Tegucigalpa, Honduras June 24, 2022. REUTERS/Fredy Rodriguez 

Children suffering symptoms of dengue fever are treated at Hospital Escuela, as authorities reported a nationwide fever outbreak, in Tegucigalpa, Honduras June 24, 2022. REUTERS/Fredy Rodriguez 

Merbin Yandel Flores lies on a hospital bed while suffering symptoms of dengue fever at Hospital Escuela, as authorities reported a nationwide fever outbreak, in Tegucigalpa, Honduras June 24, 2022. REUTERS/Fredy Rodriguez 

A patient, suffering from dengue fever, chats with a man while sitting under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, October 12, 2021. REUTERS/Fayaz Aziz 

A patient, suffering from dengue fever, lies under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, October 12, 2021. REUTERS/Fayaz Aziz TPX IMAGES OF THE DAY 

Patients, suffering from dengue fever, lies inside a mosquito net in a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, October 12, 2021. REUTERS/Fayaz Aziz 

A man helps a nurse as she draws blood for a test from a patient suffering from dengue fever inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, October 12, 2021. REUTERS/Fayaz Aziz 

A patient, suffering from dengue fever, receives medical aid as he lies under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, October 12, 2021. REUTERS/Fayaz Aziz 

A man, suffering from dengue fever, uses mobile phone as he lies under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan, October 12, 2021. REUTERS/Fayaz Aziz 

A doctor and nurse visit patients suffering from dengue fever, who lie under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan October 4, 2021. REUTERS/Fayaz Aziz 

A boy sits beside a relative patient, suffering from dengue fever, who lies under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan October 4, 2021. REUTERS/Fayaz Aziz 

Patients, suffering from dengue fever, lie under a mosquito net inside a dengue ward at Lady Reading Hospital in Peshawar, Pakistan October 4, 2021. REUTERS/Fayaz Aziz 

Cristian Jordan, 37, who suffers from dengue fever and is experiencing symptoms consistent with COVID-19, lies on his bed at his home, during the coronavirus disease (COVID-19) outbreak, in Puerto Roma, Ecuador, April 21, 2020. REUTERS/Santiago Arcos SEARCH "RURAL ECUADOR COVID-19" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. 

A federal health worker takes part in fumigation to prevent the proliferation of mosquitos that transmit the Dengue fever at the San Lorenzo National School, in a low-income neighbourhood of San Lorenzo, Paraguay February 12, 2020. REUTERS/Jorge Adorno 

A federal health worker takes part in fumigation to prevent the proliferation of mosquitos that transmit the Dengue fever at the San Lorenzo National School, in a low-income neighbourhood of San Lorenzo, Paraguay February 12, 2020. REUTERS/Jorge Adorno TPX IMAGES OF THE DAY 

A federal health worker takes part in fumigation to prevent the proliferation of mosquitos that transmit the Dengue fever at the San Lorenzo National School, in a low-income neighbourhood of San Lorenzo, Paraguay February 12, 2020. REUTERS/Jorge Adorno 

A federal health worker takes part in fumigation to prevent the proliferation of mosquitos that transmit the Dengue fever at the San Lorenzo National School, in a low-income neighbourhood of San Lorenzo, Paraguay February 12, 2020. REUTERS/Jorge Adorno 

A federal health worker takes part in fumigation to prevent the proliferation of mosquitos that transmit the Dengue fever at the San Lorenzo National School, in a low-income neighbourhood of San Lorenzo, Paraguay February 12, 2020. REUTERS/Jorge Adorno 

A health worker fumigates a residential area to curb the spread of dengue fever in Hodeidah, Yemen January 22, 2020. Picture taken January 22, 2020. REUTERS/Abduljabbar Zeyad 

Health workers check stagnant water pools which could server as potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

A health worker fumigates a residential area to curb the spread of dengue fever in Hodeidah, Yemen January 22, 2020. Picture taken January 22, 2020. REUTERS/Abduljabbar Zeyad 

A boy lies on a stretcher as he recuperates from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

Stagnant water pools which could server as potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, are pictured in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

Boys recuperate from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

People recuperate from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

Health workers inspect stagnant water pools which could server as potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

A health worker fumigates a residential area to curb the spread of dengue fever in Hodeidah, Yemen January 22, 2020. Picture taken January 22, 2020. REUTERS/Abduljabbar Zeyad 

Children recuperate from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

Health workers spray insecticides as they begin fumigating residential areas to curb the spread of dengue fever in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

A health worker fumigates a residential area to curb the spread of dengue fever in Hodeidah, Yemen January 22, 2020. Picture taken January 22, 2020. REUTERS/Abduljabbar Zeyad 

A truck pours sand on stagnant water pools to drain the potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

A man lies on a bed as he recuperates from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

A boy lies on a bed as he recuperates from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

A health worker fumigates a residential area to curb the spread of dengue fever in Hodeidah, Yemen January 22, 2020. Picture taken January 22, 2020. REUTERS/Abduljabbar Zeyad 

A boy lies on a bed as he recuperates from dengue fever at a hospital in Hodeidah, Yemen January 21, 2020. Picture taken January 21, 2020. REUTERS/Abduljabbar Zeyad 

Insects breeding are pictured on stagnant water pools which could server as potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

A health worker fumigates a residential area to curb the spread of dengue fever in Hodeidah, Yemen January 22, 2020. Picture taken January 22, 2020. REUTERS/Abduljabbar Zeyad 

Boys walk by stagnant water pools which could server as potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

A bulldozer covers stagnant water pools with sand to drain the potential breeding sites of Aedes aegypti mosquitoes, known to spread the dengue fever, in Hodeidah, Yemen January 20, 2020. Picture taken January 20, 2020. REUTERS/Abduljabbar Zeyad 

Paraguay's Health Minister Julio Mazzoleni addresses the media as Paraguay is bracing for a potential major epidemic of dengue fever, on the outskirts of Asuncion, Paraguay January 17, 2020. REUTERS/Jorge Adorno 

Workers from the National Malaria Eradication Service (SENEPA) fumigate a neighbourhood to prevent the spread of dengue fever, on the outskirts of Asuncion, Paraguay January 17, 2020. REUTERS/Jorge Adorno 

A worker from the National Malaria Eradication Service (SENEPA) fumigates a neighbourhood to prevent the spread of dengue fever, on the outskirts of Asuncion, Paraguay January 17, 2020. REUTERS/Jorge Adorno 

A man lies as he recuperates from dengue fever at a hospital in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

Nurses and relatives stand, as patients recuperate from dengue fever, at a hospital in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

People crowd a hospital, treating dengue fever patients, in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

People recuperate from dengue fever at a hospital in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

A man sits by his son as the boy recuperates from dengue fever at a hospital in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

Girls recuperate from dengue fever at a hospital in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

Children recuperate from dengue fever at a hospital in al-Jarrahi district of Hodeidah, Yemen November 17, 2019. Picture taken November 17, 2019. REUTERS/Abduljabbar Zeyad 

A worker fumigates a resident area to prevent the spread of the dengue fever and other mosquito-borne diseases in Kathmandu, Nepal September 5, 2019. REUTERS/Navesh Chitrakar 

A woman covers her face as she walks away after a worker fumigated a resident area to prevent the spread of the dengue fever and other mosquito-borne diseases in Kathmandu, Nepal September 5, 2019. REUTERS/Navesh Chitrakar 

A worker fumigates a resident area to prevent the spread of the dengue fever and other mosquito-borne diseases in Kathmandu, Nepal September 5, 2019. REUTERS/Navesh Chitrakar 

A woman covers her face as she walks along the street after a worker fumigated a resident area to prevent the spread of the dengue fever and other mosquito-borne diseases in Kathmandu, Nepal September 5, 2019. REUTERS/Navesh Chitrakar