Studies on the importance of the face Fly Musca sorbens at Kambala Village, Mvomero District, Morogoro, Tanzania

T J N K Mbilu, R S Silayo*, E N Kimbita* and S J Onditi*

Livestock Training Institute (LITI- Tengeru) PO Box 3101, Arusha, Tanzania
*Department of Veterinary Microbiology and Parasitology, Faculty of Veterinary Medicine, Sokoine University of Agriculture,
P.O. Box 3019, Morogoro, Tanzania
Togolaimbilu@yahoo.co.uk   ;   rssilayo@yahoo.co.uk

Abstract

A study was carried out to determine the importance of the face fly (Musca sorbens) at Kambala, a pastoral village situated 6⁰00`-6<sup>0</sup>30` South and 37⁰30`-38<sup>0</sup>00` East in Mvomero District , Morogoro, Tanzania. This village has had a recent re-introduction of cattle dipping for tick control. A total of 32 livestock keepers were interviewed using structured pre-tested questionnaire and data on human fly-related eye and diarrhoeal infections from five-year (2001 -2005) patient records from Kambala dispensary were obtained.

Results showed that there was 39% drop in eye infections from 2003 to 2004 concomitant with increase in dipping following rehabilitation of the village livestock dip tank and start of dipping cattle in synthetic pyrethroid acaricide. Fly population density in homesteads with livestock dipped in the synthetic pyrethroid was lower than in those homesteads where animals were sprayed with acaricide from the diamidine group. Both Musca sorbens and Musca domestica were identified in the study area and fly annoyance was observed in both cattle and man although children infested with face flies appeared more fly-tolerant than adults. The study revealed that 76.7% of households had two to five members who had encountered eye infection but there was no statistically significant difference between young and adults who once had eye infections (p>0.05). A relationship between eye infection, weather condition and high fly population density was revealed in the questionnaire study.

It is concluded that strategic dipping in synthetic pyrethroids can reduce fly annoyance and eye infections. In contrast to the eye-related infections which appeared to decrease following dipping, diarrhoeal diseases (likely associated with the house fly (Musca domestica), were on the ascendance from year to year with only a slight decrease between year 2003 and 2004.

Keywords: eye infection, face fly, Kambala, Musca sorbens

Introduction

Flies known to infest the face in animals have been known to cause annoyance and reduced feeding leading to reduction in animal productivity. These flies belong to the genus Musca and in both man and animals they also act as biological or mechanical vectors of pathogens (Greenberg 1973; Wardhaugh and Morton 1990; Graczyk et al 1999; Fischer et al 2001; Heath 2002; Muhammad and Ludeck 2004; Henning et al 2005). There are about twenty six different species of the genus Musca. These include Musca domestica, Musca autumnalis, M. sorbens, Musca xanthomelas, Musca lusoria and Musca nevilli. In temperate countries Musca autumnalis has been identified as the face fly whereas in Africa Musca xanthomelas Wedemann, Musca lusoria and Musca nevilli Kleynhans have been identified as African face flies (Kruger and Scholtz 1995; Bowman 1999). Musca sorbens has also been commonly known as the face fly in Africa but has other common names. It is known as the bazaar fly in North Africa, a house fly in India, and the bush fly in Australia (Yu 1971). It was first described from Sierra Leone in West Africa in 1830 and is closely related to Musca autumnalis which occurs in temperate countries.

Musca sorbens has the distinctive habits of not entering homes or darkened areas, not particularly being attracted to fresh food and only moderately being attracted to garbage. It feeds preferentially on cow dung and dog faeces. Morphologically, it resembles a half-sized housefly but is distinguished by its shiny, two-striped thorax. It feeds avidly from human eyes and on nasal discharge and moves purposely from eye to eye. Through this behaviour it is responsible for transmission of trachoma (Emerson et al 2001). They are also attracted to wounds, sores, and skin lesions, searching for any possible food sources such as blood and other exudations. Although not a biting species, it is capable of transmitting eye and diarrhoeal diseases to man as well as livestock due to their ability to carry pathogens on their feet, faeces and digestive juices they regurgitate (Oo Khin Nwe et al 1989; Esrey et al 1991; Curtis et al 2001). Diseases transmitted by Musca spp as a group include those caused by bacteria such as Escherichiacoli O157: H7 (Sasaki et al 2000), Yersinia pseudotuberculosis, Campylobacter jejuni, Helicobacter pylori and Salmonella spp. (Zurek et al 2001) and protozoan pathogens such as Entamoeba histolytica and Giardia intestinalis (Sales et al 2002).

Pastoral homesteads provide ample breeding sites for Musca sorbens and other Musca spp. which cause annoyance and transmit a number of diseases to man and his domesticated animals. Musca spp can be managed to some extent by sanitation measures that reduce accumulation of waste materials that serve as breeding sites (Lyon 1997). Insecticides are also used to control them, although development of insecticide resistance particularly by Musca domestica is a serious problem. Biological control is another method which can be used to control flies. This is focused on pupal parasitoid but there is a possibility of using entomopathogenic fungi, to produce mycoinsecticide baits for adult flies (Lysyk 2004; Lecuona et al 2005; Cao et al 2006).

There is a general belief that pastoralists particularly Maasai have high tolerance of face flies and thus making it possible that these flies are not very important to them in terms of annoyance. However during a study on the re-introduced dipping in Kambala village it was found the farmers appreciated the impact of the dipping on reducing face fly annoyance to them and their animals. After dipping of the cattle it was observed that the cattle were restful during the night (possibly due to less Stomoxys spp) and both owners and their animals had relief from face flies. A study was therefore carried out to look into perceptions of the pastoral people on face flies and a possible association between these flies and presence of eye and diarrhoeal disease problems in this village as well as the impact of use of dip tank in the village, on the prevalence of face flies and the mentioned disease problems.
 

Materials and methods

Study area

Kambala village (6⁰00`-6<sup>0</sup>30` South and 37⁰30`-38<sup>0</sup>00` East)in Mvomero district Morogoro region Tanzania was the study area. It has a total area of 16,000 hectares, most of which is covered with short grass, trees and shrubs that provide a wide range of pasture for livestock grazing. This area is designated for livestock keeping whereby most villagers keep cattle, goats, and few sheep. Indigenous people depend largely on livestock production. During the dry season animals are moved to Handeni in search of pasture and water. Normally the dry season starts from August to the end of November. A village dip tank which had been in disuse since early 1980's was rehabilitated in 2003 with funds from a SUA-NORAD funded research project.

Health data

The period of the study was June to August 2006. This study was based on records from Kambala dispensary (Health Management Information System) record book from 2001-2005, questionnaire and insect sampling and identification. Data on number of patients, eye infection cases and diarrhoeal cases attended for each month at Kambala dispensary from year 2001-2005 were extracted from the dispensary record books.

Questionnaire study

A total of 32 livestock keepers were interviewed using structured pretested questionnaire. It was set to determine the perception of the villagers toward faceflies, the period of high fly prevalence, control measures, association of flies and livestock and dipping of animals. Every villager had equal opportunity to be selected for interview. The questionnaire was filled in form of interview using Kiswahili for those farmers who knew Swahili language. In cases where respondent could not use Swahili language translation from the vernacular language was done. Cross checking on the acaricide used to spray animals was done by requesting to be shown used drug bottles.

Field observations and collections of flies

Observations of animals in their "boma" as well as their surroundings were carried out. According to how flies were conspicuous it was recorded as area with very high fly population density followed by high, low as well as very low fly density. Also photographs of flies on animals were taken.

Flies were collected from animal and human head region using a hand net. They were stored in small bottles containing 70% alcohol. Collected flies were examined and identified at the parasitology laboratory, Faculty of Veterinary Medicine, SUA using the key described by Greenberg (1971).

Statistical analysis

Collected data were entered in Epi-info database (Coulombier et al 2001) and statistical differences between proportions were determined using Epi-info 6 Epitable program with the critical probability of p=0.05. Figures were drawn using Microsoft excel programme.
 

Results

Respondents asked on problems associated with presence of face flies indicated that they cause a lot of annoyance. Animals infested with flies on the faces (Figure 1) were observed to shake their heads frequently. Due to this they also appeared to feed less. Fly annoyance on man was particularly observed on adults. Children infested with the flies on their faces appeared more tolerant.

Average human eye and diarrhoeal infections at Kambala village in five years range (2001-2005) are shown in Figure 2. It can be observed that there is a notable drop in percentage eye infection cases between year 2003 and 2004.

About 75% of the respondent households indicated they had had at least one child and adult who had eye infections. However, there is no statistically significant difference between adult and child eye infections in households (p> 0.05) (Figure 3)

Population density of flies was low on those animals which are dipped using synthetic pyrethroid (Dominex®), when compared to those animals where diamidine (Tixfix®) is used for spraying (Figure 4).

From the study 80.6 % of respondents reported that flies population density is very high during rainy season. Also 66.7% reported the occurrence of eye problems in the same rainy season (Figure 5)

The total number of flies collected for identification was 239. Out of these, 110 (46%) were Musca sorbens, 103 (43.1%) were Musca domestica and 26 (10.9%) were non-Musca species. There was no statistically significant difference (P> 0.05) among Musca sorbens and Musca domestica. High percentage of Musca domestica was collected from households using the synthetic pyrethroid Dominex® for tick control on their animals (Figure 6).

Discussion and conclusions

Insect control is an important component of control strategies against vector-borne diseases of man and animals. In order to put in place effective and economical control strategies, importance of the insects under question should be known as well as prevailing control measures. This study was aimed at determining the importance of face flies at Kambala village and the impact of re-introduced acaricide application on animals.

In this study it was found out that flies caught from faces of animals and man at Kambala village comprised 46% Musca sorbens, 43.1% Musca domestica and 10.9% flies other than Musca spp. The presence of Musca sorbens known to transmit trachoma, infectious bovine keratoconjunctivitis and other bacterial eye infections (Emerson et al 1999) points to the possibility that some of the eye infections may be associated with this fly. Contrary to widely held belief concerning Maasai and face flies, Maasai adults at Kambala appeared not to tolerate face flies. In contrast more fly tolerance was observed among children although this did not translate to higher prevalence of eye infections in children as the study showed there was no statistically significant difference between child and adult eye infections.

Results show the presence of eye infection problem in man and animals at Kambala village, was more prevalent during the rainy season in correlation with high fly population. Reinhards et al (1968) reported the association of flies and eye diseases in Southern Morocco. In trachoma endemic areas, epidemics of bacterial conjunctivitis and increases in the prevalence of active trachoma have been observed following peaks in the fly population (West 2003; Johnson 2004).

There was a decrease in human eye infection cases from 2001 to 2005 with a dramatic drop between 2003 and 2004. This could be explained into two ways. One is the improved hygiene which reduces the possibility of bacterial eye infection as pointed out by Chavasse et al (1999). Two, is the use of insecticide either purposively for the control of face flies or intended for other flies. In the study area animals were being dipped in a synthetic acaricide Dominex®, which was also an effective insecticide. Results show that, there was a low face fly population density at homesteads where animals were being dipped in the synthetic pyrethroid (Dominex®) which was both acaricidal and insecticidal compared to those homesteads where tick control was by application of a non-pyrethroid acaricide (Tixfix®) which had no significant residual insecticidal effect. This showed that the synthetic pyrethroid (Dominex®) played a role in controlling flies which can act as vectors for animal and human diseases.

Results from the present study showed an increase in human diarrhoeal cases from 2001 - 2005 as opposed to a drop in eye infections. Musca domestica is one of most important transmitters of diarrhoeal diseases and also can be involved on mechanical transmission of bacterial eye infections but apart from the fly involvement in transmission of diarrhoeal pathogens, poor hygiene and water shortage are also factors involved in increased number of diarrhoeal cases.

Face flies appear to have direct and indirect effects on animal production and rural development. They have direct effect on animal production through causing annoyance and eye infection when infesting animals. However, when they infest man the annoyance and eye infections caused have a bearing on animal production since the annoyance and eye infections could possibly make the pastoral areas appear lest attractive living areas than other areas (e.g. urban). Eye infections are likely to reduce man-hours available for tending grazing livestock as the affected adults or children may need visits to the hospital. Additionally, money which should have been spent on animal production is spent against human diseases controllable by face-fly control. Dipping animals in synthetic pyrethroids appeared to have inadvertent positive effect of also controlling face flies at Kambala and therefore livestock keeper should be educated on this indirect advantage of dipping their animals for tick control.
 

Acknowledgement

We acknowledge the livestock keepers of Kambala Village for their consent and cooperation during this research. Sincere gratitude also goes to the District Medical Officer- Mvomero) and his staff for permission and assistance in retrieval of data on eye and diarrheal infections. Mr. Isaya Rijiwa, one of the leaders at Kambala village, is thanked for his assistance during questionnaire administration and collection of livestock data. We would also like to express gratitude to Mr Kindamba A. Lekaki (Principal Technician in the Department of Veterinary Microbiology and Parasitology) for his technical assistance during the laboratory work. Also we thank the Government of Tanzania through the Ministry of Science, Technology and Higher Education for the loan offered to the senior author (TJNKM) for this research work.
 

References

Bowman D 1999 Georgis' Parasitology for Veterinarians (7^th Edition). W B Saunders company. London. 11-18 pp

Cao X M, Song F L, Zhao T Y, Dong Y D, Sun C X and Lu B L 2006 Survey of Deltamethrin Resistance in House Flies (Musca domestica) from Urban Garbage Dumps in Northern China. Environmental Entomology 35 (1): 1-9

Chavasse D C, Shier R P, Murphy O A, Huttly S R A, Cousens S N and Akhtar T 1999 Impact of fly control on childhood diarrhoea in Pakistan: a community-randomised trial. Lancet 353; 22-25.

Coulombier D, Fagan R, Hathock L and Smith C 2001 A Word Processing, Database and Statistics Program for Public Health. Centers for Disease Control and Prevention, Atlanta, Georgia.

Curtis V, Cairncross S and Yonli R 2001 Domestic hygiene and diarrhoea-pinpointing the problem. Tropical Medicine and International Health, Volume 5 (1): 22-32

Emerson P M, Bailey R L, Walraven G E L, Lindsay S W 2001 Human and other faeces as breeding media of the trachoma vector Musca sorbens. Medical and Veterinary Entomology 15 (3): 314-320.

Emerson P M, Lindsay S W, Walraven G E, Hannah Faal, Bøgh C, Lowe K and Bailey L R 1999 Effect of fly control on trachoma and diarrhoea. Lancet 353: 1401-1403.

Esrey S A, Potash J B, Roberts L and Shiff C 1991 Effects of improved water supply and sanitation on ascariasis, diarrhoea, dracunculiasis, hookworm infection, schistosomiasis, and trachoma. Bulletin of the World Health Organization 69(5): 609-621. http://whqlibdoc.who.int/bulletin/1991/Vol69-No5/bulletin_1991_69(5)_609-621.pdf

Fischer O, Matlova L and Dvorska L 2001 Diptera as vectors of mycobacterial infections in cattle and pigs. Medical and Veterinary Entomology 15: 208-211.

Graczyk T K, Cranfield M R, Fayer R and Bixler H 1999 House Flies (Musca Domestica) as transport hosts of Cryptosporidium parvum. American Journal of Tropical Medicine and Hygiene 61(3): 500-504

Greenberg B 1971 Flies and Disease, Volume 1, Ecology, Classification and Biotic Associations, Volume 1, Biology and disease transmission. Princeton University Press, Princeton, U.S.A.

Greenberg B 1973 Flies and Disease, Volume 1, Ecology, Classification and Biotic Associations, Volume 2, Biology and disease transmission. Princeton University Press, Princeton, U.S.A.

Heath A C G 2002 Distribution, seasonality and relative abundance of Stomoxys calcitrans (stablefly) (Diptera: Muscidae) in New Zealand. New Zealand Veterinary Journal 50: 93-98.

Henning J, Schnitzler F R, Pfeiffer D U and Davies P 2005 Influence of weather conditions on fly abundance and its implications for transmission of rabbit haemorrhagic disease virus in the North Island of New Zealand. Medical and Veterinary Entomology 19: 251-262

Johnson G J 2004 The environment and the eye. Eye, 18: 1235-1250

Kruger K and Scholtz C H 1995 The effect of ivermectin on development and reproduction of the dung breeding fly (Musca nevilli Kleynhans (Diptera, Muscidae). Agriculture, ecosystems and environment 53: 13-18

Lecuona R E, Turica M, Tarocco F and Crespo D C 2005 Microbial Control of Musca domestica (Diptera: Muscidae) with Selected Strains of Beauveria bassiana. Journal of Medical Entomology 42 (3): 332-336

Lyon F W 1997 Domestic Flies Pet Pest Management, Ohio State University Extension Bulletin 586 at http://ohioline.osu.edu/b586/b586_11.html visited on 27^th June 2006

Lysyk T J 2004 Host Mortality and Progeny Production by Solitary and Gregarious Parasitoids (Hymenoptera: Pteromalidae) Attacking Musca domestica and Stomoxys calcitrans (Diptera: Muscidae) at Varying Host Densities. Environmental Entomology 33 (2): 328-339

Muhammad J A and Ludek Z 2004 Association of Escherichia coli O157:H7 with houseflies on a cattle farm. Applied and Environmental Microbiology 70 (12): 7578-7580

Oo Khin Nwe, Sebastian A A and Aye Tin 1989 Carriage of enteric bacterial pathogens by house flies in Yangon, Myanmar. Journal of Diarrhoeal Diseases Research 7: 81-84

Reinhards J, Weber A, Nizetic B, Kupka K and Maxwell-Lyons F 1968 Studies in the epidemiology and control of seasonal conjunctivitis and trachoma in Southern Morocco. Bulletin of World Health Organization 39: 497-545. http://whqlibdoc.who.int/bulletin/1968/Vol39/Vol39-No4/bulletin_1968_39(4)_497-545.pdf

Sales M de Senna Nunes, da Costa G L and Bittencourt Pinheiro V R E 2002 Isolation of Fungi in Musca domestica Linnaeus, 1758 (Diptera: Muscidae) Captured at Two Natural Breeding Grounds in the Municipality of Seropédica, Rio de Janeiro, Brazil Mem Institute Oswaldo Cruz, Rio de Janeiro 97(8): 1107-1110 http://www.scielo.br/pdf/mioc/v97n8/4558.pdf

Sasaki T, Kobayashi M and Agui N 2000 Epidemiological Potential of Excretion and Regurgitation by Musca domestica (Diptera: Muscidae) in the Dissemination of Escherichia coli O157: H7 to Food. Journal of Medical Entomology 37 (6): 945-949

Wardhaugh K G and Morton R 1990 The incidence of flystrike in sheep in relation to weather conditions, sheep husbandry, and the abundance of the Australian sheep blowfly, Lucilia cuprina Wiedemann (Diptera: Calliphoridae). Australian Journal of Agricultural Research 41:1155-1167

West S K 2003 Blinding trachoma: prevention with the safe strategy. American Journal of Tropical Medicine and Hygiene 69 (Supplement 5): 18-23

Yu Hyo-Sok 1971 The biology and public health significance of Musca sorbens Wied. in Hawaii. M. Sc Thesis, University of Hawaii. 72 p

Zurek L, Denning S S, Schal C and Watson D W 2001 Vector Competence of Musca domestica (Diptera: Muscidae) for Yersinia pseudotuberculosis. Journal of Medical Entomology 38 (2): 333-335

Received 12 December 2006; Accepted 23 February 2007; Published 2 April 2007

Go to top