Could howler monkeys harbour zika virus?

Zika belongs to the group of flaviviruses spread by mosquitoes and ticks, a group that includes Yellow Fever Virus [YFV], dengue, chikungunya and tick borne encephalitis. YFV is well known to infect non-human primates: chimpanzees in Africa. When slave ships spread YFV to the Americas new hosts emerged such as Howler monkeys. In the Carribean during the nineteenth century it was noted that human epidemics of YFV were often predated by multiple deaths of howler monkeys. Mosquitoes bite humans, primates, mammals, birds and reptiles so a new 'sylvatic' cycle of infection involved loggers and rural farmers through transfer from a reservoir of virus surviving in birds, rats or monkeys. 

This cycle could overlap with the urban cycle involving two mosquitoes: Aedes aegypti and Aedes albopictus for instance at markets and logging centres. In this way the disease became endemic, ie permanent and impossible to eradicate since it was well established in non-human populations. Fortunately YFV is now controlled by an effective vaccine, however Zika has no known treatment.
  Whether Zika has developed a sylvatic cycle in the Americas is a matter of speculation. Zika has been shown to infect apes in Africa but no one has studied New World monkeys in the same way. Zika is in any case difficult to detect as it only appears transiently in the blood stream.
Background info here: 

Detecting Zika virus infection

A recent study [1] reveals that patients with symptoms of Zika virus have detectable virus RNA [by RT-PCR] in the serum within two days of the onset of symptoms when urine samples remain negative.  

However at four days after onset viral RNA is detectable in the urine at higher levels and [Asian lineage] RNA remains detectable in urine for longer: up to 14 days after onset of symptoms. 

1. Prolonged detection of Zika virus RNA in urine samples during the ongoing Zika virus epidemic in Brazil Campos, R de M. Cirne-Santos C, Meira GLS et al, 

Journal of Clinical Virology, 2016-04-01, Volume 77, Pages 69-70, 

Why is Zika risk under or over-estimated? Recent papers

An article form the Infectious Diseases Study Group in Queensland, Australia on April 19 2016 [Gyawali, Narayan; Bradbury, Richard S; Taylor-Robinson, Andrew W; NLM. Infectious diseases of poverty5.1: 37.]  seeks to balance media reports of '2.1 billion people at risk' with the recent experience of Dengue, with no vaccine, theoretically also capable of spread to the United States and Australia. Their discussion reads: 

"Despite understandable concern among the general public that has been fuelled by the media, in regions where Zika is not present, such as North America, Europe and Australia, at this time any outbreak (initiated by an infected traveler returning from an endemic area) would very probably be contained locally."

   The main reasons they cite are the limited distribution of mosquitoes and less dense centres of population. Well developed infrastructure, covered drains and improved nutritional status may also contribute. 
   It is possible to find apparently scientific papers making dire predictions of numbers of people at risk: 

Mapping global environmental suitability for Zika virus

Messina, Jane P; Kraemer, Moritz Ug; Brady, Oliver J; Pigott, David M; Shearer, Freya M; et al. eLife 5 (Apr 19, 2016) 

So the media hype is understandable. But this creates difficulties for reporters who fail to distinguish peer-reviewed papers from internet publications which lack thorough critique.

Animations of Dengue virus

There are plenty of scary videos of mosquitoes drinking blood

But here I'll explore animations of Dengue, a virus which is closely related to Zika virus.

Dengue (for kids) a compilation of two films: the first a cartoon with a mosquito song showing used tyres, insecticide and emptying water containers. 

Followed by a more sophisticated 3D cartoon called 'A holiday with granny' narrated by a woman warning about the danger of cut flowers in the house providing a breeding site for mosquitoes. The first film is short and to the point. The second is well-crafted with four different human characters and several mosquitoes but it's long and slow to reach its climax.

Life cycle of the Dengue virus

HHMI bioactive video

A superbly made but highly technical 3D animation of virus entry into the cell and taking over the hosts protein synthesis. Serious queen's English narration. Beautifully illustrates RNA synthesis and the structure of a single cell. Visually stunning, non-explanatory to lay people.

The Dengue fever movie [English subtitles are available, though they are incoherent] 

After various news reports of a Dengue outbreak, the film folows the life cycle of the mosquito probing for blood vessels. Salivary secretions are shown entering the blood stream. Dengue virus shown symbolically reaching the mosquito's salivary glands.

Top 5 Zika websites

Top Five sites for up-to-date information about Zika virus

1. The CDC shows the number of US cases of Zika to date and how they were acquired. 

There's also good advice on how to avoid mosquito bites, how to combine insect repellant and sun cream and how to treat infants.In addition, CDC Travel Health Notices give warnings about countries with active outbreaks of Zika: 

recent warnings include Fiji, Puerto Rica and Cuba.

2. The PAHO, Pan American Health Organisation has an interactive map which shows the number of countries with Zika cases and the number of cases in each country. 

Also avaialable as a table showing the number of suspected cases. There's advice for pregnant mothers and information about microcephaly.

3. The NHS Choices site has recommendations for reducing your risk of Zika:

4. The BBC site gives sound advice and recommends using insect repellants containing picaridin as well as DEET.

However, as you can see this map is not fully up-to-date

5. A WHO map shows the number of confirmed microcephaly cases in Brazil.

Zika virus films: a review

There are several short animations about Zika virus, five of which I will review here.

1. How Zika spreads (and who's to blame) a one minute infomatic by Sohail Aljamea.
Malaria as the most dangerous disease spread by Aedes aegypti but the film focuses on the danger of yellow fever rather than dengue, a much more widespread condition which unlike yellow fever, has no available vaccine. A map of the United States showing the distribution of Aedes mosquitoes as far north as Iowa, Ohio and New York does not correspond to the likely areas of spread of Zika; the virus thrives in areas of warm temperature, dense population, open drains which are largely absent from the areas shown in red on the map.
The information is essentially accurate but the style is dramatic and might cause non-professionals to overestimate the risk of Zika infection in many of the 30 American states implicated.
Who's to blame? Presumably the Aedes aegypti mosquito, rather than any person or government.

2. "O odioso do Egito".Watch with English subtitles. roughly translated as 'Hateful from Egypt'. A mainly black and white 'woodcut style' animation from Brazil's ministry of Health, accompanied by a song in Portuguese. The film begins with a wanted poster for the mosquito. Three closely related viruses are shown: Zika, dengue and Chikungunya. Mosquito larvae are shown in an open bottle. Rain highlights the danger of any open water, Insecticide is spread on water and earth is added to the base of pot plants, a lid is put on  a water tank.
While the control measures are vital, Aedes aegypti has some defences against each of these measures: by living outside houses, laying eggs above the water level, having eggs that hatch after variable intervals, being resistant to many insecticides and entering through fine gaps to breed in covered tanks.

3. A scientifically accurate model of the Zika virus. Visually stunning, tactile, silent film showing the RNA in the centre of the the virus, protein capsid, lipid membrane and the triangular arrangements of enveloipe proteins. Probably of most use to people already familiar with an understanding of viral structure. A fascinating insight but the lack of comparative scale might make people think the virus is larger than 10nm. Doesn't explain any biological properties of the virus.

4. From Aedes to Zika: what we know and what we don't A scientifically sound film in which Professor Jason Rasgon puts the disease in context with a list of symptoms and a map showing the spread of Zika in the last twenty years. 4/5 people have no symptoms but may be carriers of the disease. Infants with microcephaly are shown. Although the link is unproven, RNA virus particles from Zika have now been isolated from a child with microcephaly, supporting a causal link. Insecticides are shown being sprayed in towns in Brazil.
.

5. Alerta Dengue, Chikungunya e Zika A health information film in Portuguese encouraging four preventive steps: 

Use insecticide, cover water, remove water from old tyres and fill the bases of plant pots.