Was there malaria in prehistoric Ireland?

 

The range of mosquito species Anopheles claviger (Meigen) from diptera-culcidae.0catch.com

The range of mosquito species Anopheles Claviger (Meigen) in grey from diptera-culcidae.0catch.com

Malaria could partly explain the widespread iron-deficiency anaemia seen in Irish Early Bronze Age cemeteries.

I am spending this summer writing a book on Ireland in the Bronze Age and at the moment I am working on a section on human health. The evidence from cemeteries where there is adequately preserved skeletal material, and these remains have been analysed for pathology, indicates that there was widespread iron-deficiency anaemia amongst the population, both children and adults. These deficiencies present in the preserved bone as porotic hyperostosis and cribra orbitalia while dental hypoplasia indicates acute infection and fever. So far I have noted instances in a dozen cemeteries in Connacht, Leinster, Munster and Ulster and there are probably more. Usually in the reports these diseases are interpreted as indicating a population that was poorly adapted to its environment or was under nutritional stress.

However I know from the sections that I have written on settlement and farming that today the areas in which these cemeteries are found are amongst the most fertile regions of Ireland and the fields surrounding these cemeteries, if not built on, are used to fatten cattle and grow cereals. When I look at the archaeological and palynological evidence for agriculture it indicates that Early Bronze Age farming was generally small-scale and often carried out in in clearings in the forest close to water that were restricted to the lighter and better drained lowland soils (Weir 1995). These clearings were laboriously made by hand to provide grazing land for cattle and pigs with some sheep and horses. There was some cereal cultivation of both wheat and barley but this appears to have been on a limited scale although preserved wheat and barley has been found at a number of settlement sites. The resources of the surrounding forest were also used and hazel nuts, wild apples and berries were collected. The farmers also hunted and the remains of red deer, wild boar and hare have been found at settlements.

The pollen evidence indicates a gradual clearance of forest surrounding the settlements. For example at Roughan Hill, Co. Clare a system of irregularly-shaped fields enclosed by stone walls was laboriously cleared from the forest and contained dispersed houses within enclosures and family tombs covering an area of about 144 hectares (Note Roughan Hill is now dated to the Early Bronze Age see Jones 2008). An area this size might have produced 200-300 cattle annually as well as some cereals and there were all the resources of the surrounding forest. Settlements of the period were usually small scale consisting of just one or two houses for perhaps a single family group. The skeletal remains of the farmers tell the story of the hard work of cutting down trees, removing stones from fields and building stone walls. Many people suffered from injured backs with Schmorl’s nodes, periostitis, degenerative joint disease and osteoarthritis. In my view the archaeological evidence suggests that the Early Bronze Age people were quite well adapted to their environment and don’t appear to have been outstripping the available resources. So I am not happy with widespread nutritional stress as an explanation for the anaemia.

An alternative explanation is that a low level of iron in the blood may be a defence against pathogens. During infection iron is sequestered in the liver, which prevents invading pathogens from getting adequate supplies of this vital element. If these people were being affected by a pathogen it would have to be one that could spread to small-scale low-density communities living close to rivers, lakes and bogs. Diseases like Typhus usually require a higher density of settlement to spread, however mosquito-borne pathogens are a possibility. Recent investigations of Egyptian Royal mummies, for example, have identified the DNA of Plasmodium falciparum, the malaria parasite in association with porotic hyperostosis, so the anaemia could be indicating malaria (Nerlich et al. 2008).

Although Ireland no longer has any mosquito-borne pathogens, it did in the past. Irish mosquitoes are known to have spread tertian malaria (Plasmodium vivax) and the last major outbreak occurred in Cork in the 1840s, 50s and 60s. As well as malaria mosquitoes also have the potential to spread yellow fever, dengue fever and encephalitic viruses. Today Ireland has 18 species of mosquitoes of which four are Anopheles (including Anopheles Claviger (Meigen)) the potential carriers of malaria. Although mosquitoes have not been recorded in archaeological or palaeoenvironmental samples they occur throughout Europe and were first scientifically recorded in Ireland in 1823 (Ashe et al.1991). From the environmental perspective during the Early Bronze Bronze Age the climate is thought to have been 1-2° warmer than today and provided a satisfactory environment for mosquitoes to breed. In fact the Irish climate is still viable for mosquitoes and some health workers fear that climate change could see the re-emergence of malaria in Ireland in the future.

So an alternative hypothesis to the suggestion that all the iron-deficiency anaemia seen in Early Bronze Age remains is caused by nutritional deficiency could be the presence of a pathogen or pathogens that triggered the anaemic reaction as a defence mechanism. This pathogen could have been malaria which was present in Ireland in the nineteenth century. In this scenario the opening up of the forest canopy close to rivers, lakes and bogs altered the ecology and provided new habitats for mosquitos to colonise. The increased populations of mosquitoes bred in close proximity to humans and spread malaria or other pathogens that caused the anaemic reaction. Although there is currently no direct evidence for mosquito-borne pathogens in the Bronze Age Ireland I think this is a useful hypothesis that is worth further consideration and testing.

References

Ashe, P., O’Connor, J.P. and Casey R.J. 1991. Irish mosquitoes (Diptera: Culicidae): a checklist of the species and their known distribution. Proceedings of the Royal Irish Academy, Vol. 91B, 21-36.

Jones, C. 2008. Roughan Hill prehistoric landscape. In M. Comber and C. Jones (compilers) Burren Landscape and Settlement, unpblished report for the Irish National Archaeological Research programme, 42-53.

Nerlich, A.G., Schraut, B., Dittrich, S., Jelinek, T and A.R. Zink 2008. Plasmodium falciparum in Ancient Egypt. Emerging Infectious Diseases 14(8): 1317-1318.

O’Sullivan, M. 2005. Duma na nGiall The Mound of the Hostages, Tara. Dublin.

Weir, D. 1995. A palynological study in County Louth. Discovery Programme Reports 2, 77-126.

 

About the author

Dr. Charles Mount has been involved in research on the Irish Bronze Age for more than twenty years and carried out his post-graduate and doctoral research on the period. Since then he has published extensively on the burials, monuments and artefacts of the period. This blog post is partly based on research he is preparing for a book on the period Ireland in the Bronze Age. You can learn more about Charles Mount’s publications here.

Mount, C. Was there malaria in prehistoric Ireland?. The Charles Mount Blog, 5 July 2012. http://charles-mount.ie/wp/?p=883

Identifying pottery fire-pits in the archaeological record

Cloghabreedy, Co. Tipperary Site 125.3

Probable pottery fire-pits at Cloghabreedy, Co. Tipperary Site 125.3. Image from McQuade et al. 2009.

Thanks to the work of the UCD Centre for Experimental Archaeology it may now be possible to identify the pottery fire-pits of the Irish prehistoric pottery industry.

One of the most characteristic artefacts of the Irish Bronze Age is pottery. It was produced in large quantities and is found at all types of sites from settlement and ritual to industrial. Until recently no prehistoric pottery fire-pits, where the clay is heated until it becomes pottery, had been identified in the Irish archaeological literature (see for example Ó Faoláin and Northover 1998, 73). Even where quite large settlement sites have been investigated like Corrstown, Co. Derry, where over 9,000 sherds of pottery were recovered, and Chancellosrland site A, where over 2,000 sherds were found, no fire-pits were identified.

UCD Centre for Experimental Archaeology fire-pit.

UCD Centre for Experimental Archaeology fire-pit with charcoal and pottery in situ. Photo Aidan O'Sullivan

Now thanks to the work of the UCD Centre for Experimental Archaeology it looks as though firing sites can be identified. At UCD Aidan O’Sullivan, Conor Mcdermott, Thomas Cummins and John Nicholl have been making vessels of various periods and types and firing them in sub-rectangular shaped fire-pits. Once the contents of the pits have cooled and the finished pots are removed what is left is a fire-reddened pit filled with charcoal and any sherds of failed pots. The great value of this experimental work (and documenting it with images and video through media like Facebook) is that it helps archaeologists identify these features in excavation reports. Aidan O’Sullivan and the others have not only demonstrated how pottery can be made in a simple fire-pits, but Aidan has noted that the field archaeologist will find.

“Charcoal, ash, burnt stones, and pieces of fire-reddened and blackened soil. You might also find heavily fired and black, sooted pottery fragments, the fragmentary remains of previously failed pots that have been through several kiln fires.”

He also noted:

“The effect of a north-easterly breeze, meaning that only centimetres away on the ‘wrong’ side, the fire was essentially cool”.

So some method of blocking the prevailing airflow across the surface of the fire-pit is needed to maintain a constant temperature. As Graham Taylor who writes pottedhistory has noted:

“If the wind is gusting it can cause huge temperature fluctuations which destroy pots.”

The wind can be mitigated by the erection of a simple wattle screen across the path of the prevailing wind.

As Graham Taylor points out:

“A common technique would be: fairly serious fire in the pit allowed to burn down to charcoal, green brushwood directly onto this, pots on to this, then more dry fuel, close over with green brush and clay leaving a few small air holes around the edge. Walk away and leave it for a couple of days. If you’ve got it right, and it doesn’t go out, it’s a gentler way to fire larger pots and get them black.”

The sealing material may be dug from a pit or pits next to the fire-pit which may be refilled with the waste charcoal and sherds of any failed pots from the fire-pit.

Therefore the elements that one might expect to find at a pottery firing site are a fire-reddened pit or pits filled with charcoal, ash, sherds of failed pots with a windbreak to the west or south and pits from which soil has been dug to seal the fire-pit. These pits can be back-filled with the sooty failed pot sherds from the firing.

Plan of probable pottery fire-pits at Cloghabreedy, Co. Tipperary site 125-3.

Plan of probable pottery fire-pits at Cloghabreedy, Co. Tipperary site 125-3. from McQuade et al. 2009.

At Cloghabreedy, Co. Tipperary a site appears to fulfil all of these criteria. The site was excavated under the Direction of Colm Moriarty in advance of the construction of the N8 Cashel to Mitchelstown Road Scheme and is published by Colm in M. McQuade, B. Molloy and C. Moriarty (Eds.) In the Shadow of the Galtees. Archaeological excavations along the N8 Cashel to Mitchelstown Road Scheme. NRA Scheme Monographs 4, 30-31. The site consists of two sub-rectangular pits set in a line and aligned north-west to south-east with concave profiles that measure 1.37m and 1.65m long by 0.97m and 1.25m wide and 0.25m deep. The sides and bases of the pits were fire-reddened and contained charcoal fills.

Just to the east of the fire-pits was a pair of pits also filled with charcoal-rich deposits and sherds of food vessel vase and urn. Charcoal from the primary fill of one of the pits was radiocarbon dated to 2289-2014 Cal BC (UB-7377). Set 3.3m south of the fire-pits and aligned roughly east-west were nine stake-holes that appear to have supported a windbreak 7m long. This appears to have been a pottery firing site in which the leather hard vessels were placed into the fire-pit, fired under a layer of soil from the pits and then, after cooling, the material from the fire-pits was deposited back into the pits along with sherds of failed pots.

Cloghabreedy is a good example of a fire-pit because it has a number of elements, is a single period site without the complication of earlier or later features and was well excavated and published. However, where fire-pits lack associated pot sherds or windbreaks or are separated from these features by later elements recognition becomes more difficult. The conclusion is that using the insights being gained at the UCD Centre for Experimental Archaeology it will be easier in future to identify the firing sites of the prehistoric pottery industry.

References

Ó Faoláin, S. and Northover, J.P.  1998. The Technology of Late Bronze Age Sword Production in Ireland, The Journal of Irish Archaeology, Vol. 9 (1998), pp. 69-88

About the author

Dr. Charles Mount has been involved in research on the Irish Bronze Age for more than twenty years and carried out his post-graduate and doctoral research on the period. Since then he has published extensively on the burials, monuments and artefacts of the period. This blog post is partly based on research he is preparing for a book on the period. You can learn more about Charles Mount’s publications here.

Cite this post as:

Mount, C. Identifying pottery fire-pits in the archaeological record. The Charles Mount Blog, 9 May 2012. http://charles-mount.ie/wp/?p=825.

Ireland in the Bronze Age: Help Wanted

Author requests help from the public in writing a book.

Those of you who have been following this blog or have been a recipient of my emails from time to time are aware that I’ve been collecting material for a book on the Irish Bronze Age. For the last number of years I have been collecting, collating and digesting the many hundreds of reports of Bronze Age sites excavated in Ireland. My thanks go to everyone who has allowed to me to read their reports in advance of publication. Continue reading