Maria Vang Johansen - Academia.edu (original) (raw)

Papers by Maria Vang Johansen

Sehistosoma boris-infected goats were treated with praziquantel (60 mg/kg) and killed for examina... more Sehistosoma boris-infected goats were treated with praziquantel (60 mg/kg) and killed for examination 1, 7 or 28 days later. Infected non-treated goats and parasite-free, treated or non-treated goats were included for comparison. The gross pathological changes seen in the infected non-treated groups were mild to moderate. The liver appeared discoloured and moderately enlarged. The intestinal lesions were most prominent in the small intestines, which showed catarrhal inflammation with numerous tiny corpuscles beneath the luminal surface. The mesenteric lymph nodes were slightly to moderately enlarged. In contrast, on macroscopical examination, the infected treated groups invariably showed pronounced liver changes and marked enlargement of the lymph nodes, whereas the lesions in the intestines were comparatively slight. Histological lesions related to dead worms were seen in the livers of all treated animals. These lesions included pronounced inflammatory cellular infiltrates, thrombophlebitis, necrosis and periportal fibrosis, still severe 4 weeks after treatment. In the intestines, the deposition of new eggs with little cellular reaction had almost completely ceased 1 week after treatment. Four weeks after treatment, only a very few egg-associated lesions were noted in the intestines. The presence of severe lesions attributable to dead worms in the liver indicates the need for caution when treating animals with high worm loads or concomitant liver disease.

Journal of Helminthology, 2018

The presence and distribution of various species of canine hookworms in Africa are poorly known. ... more The presence and distribution of various species of canine hookworms in Africa are poorly known. The main objective of this study, therefore, was to identify the hookworm species present in canine faecal samples from Morogoro, Tanzania, using molecular techniques. Faecal samples from 160 local dogs were collected and hookworm positive samples processed to recover larvae for further molecular characterization. DNA was extracted from pools of larvae from individual samples (n = 66), which were analysed subsequently using two different molecular approaches, polymerase chain reaction-linked restriction fragment length polymorphism (PCR-RFLP) and species-specific PCR coupled with Sanger sequencing. The PCR-RFLP technique detected only the presence of the ubiquitousAncylostoma caninumin the 66 samples. However, by species-specific PCR coupled with Sanger sequencing we identified ten samples withA. braziliense, two withUncinaria stenocephalaand five withA. ceylanicum. Thus, all four known ...

Foodborne Parasites in the Food Supply Web, 2015

Abstract Pork, which is commonly consumed all over the world, may contain a number of zoonotic pa... more Abstract Pork, which is commonly consumed all over the world, may contain a number of zoonotic parasites; in this chapter, we focus on the tree T s: Taenia solium , Toxoplasma gondii , and Trichinella spiralis . Globally these parasites are listed among the most important foodborne parasites. Clinical signs in humans vary from asymptomatic or mild unspecific general malaise to severe allergic reactions, neurological disorders, and even death. The chapter briefly reviews where they occur, entry points, methods currently available for diagnosis and detection, risk factors, and points of control. Additionally, future trends in pig production and consumer habits, which are likely to affect prevalence of these parasites in pork and risk of infection in humans, are discussed.

Acta Tropica, 1994

The association between Schistosoma mansoni infection and kidney lesions was investigated in scho... more The association between Schistosoma mansoni infection and kidney lesions was investigated in school children selected from three primary schools in Machakos District, Kenya, namely Miu (n = 159), Kitengei (n= 160) and Misuuni (n=99) schools. The children were examined parasitologically for S. mansoni infection, clinically for enlargement of the liver and spleen, and biochemically for proteinuria and serum and urine creatinine. High prevalences of S. mansoni infection, ranging from 84-96%, were seen in all the schools, but the geometric mean intensity of egg excretion varied, being relatively low in Misuuni (31 eggs/g), medium in Miu (182 eggs/g) and high in Kitengei (413 eggs/g). The prevalence of pathological proteinuria (>200 mg/1) in the schools ranged from 10.1% in Miu to 28.8% in Kitengei. No difference in the levels of proteinuria was noted between age or sex groups. No association between intensity of infection and pathological proteinuria was observed in any of the schools, nor was any correlation between organomegaly and proteinuria observed. However, significant correlations between malaria and organomegaly (p<0.001) and between malaria and proteinuria (p<0.05) were observed when pooling data from all schools. These fmdings suggest that S. mansoni induced nephrotic syndromes are not common in children from this highly endemic area of Kenya.

Parasite Epidemiology and Control

Parasites & Vectors, 2019

Background: Taenia solium, a zoonotic tapeworm, is responsible for about a third of all preventab... more Background: Taenia solium, a zoonotic tapeworm, is responsible for about a third of all preventable epilepsy human cases in endemic regions. In Europe, adequate biosecurity of pig housing and meat inspection practices have decreased the incidence of T. solium taeniosis and cysticercosis. Pigs slaughtered at home may have been raised in suboptimal biosecurity conditions and slaughtered without meat inspection. As a result, consumption of undercooked pork from home slaughtered pigs could pose a risk for exposure to T. solium. The aim of this study was to quantify the risk of human T. solium exposure from meat of home slaughtered pigs, in comparison to controlled slaughtered pigs, in European countries. A quantitative microbial risk assessment model (QMRA) was developed and porcine cysticercosis prevalence data, the percentage of home slaughtered pigs, meat inspection sensitivity, the cyst distribution in pork and pork consumption in five European countries, Bulgaria, Germany, Poland, Romania and Spain, were included as variables in the model. This was combined with literature about cooking habits to estimate the number of infected pork portions eaten per year in a country. Results: The results of the model showed a 13.83 times higher prevalence of contaminated pork portions from home slaughtered pigs than controlled slaughtered pigs. This difference is brought about by the higher prevalence of cysticercosis in pigs that are home raised and slaughtered. Meat inspection did not affect the higher exposure from pork that is home slaughtered. Cooking meat effectively lowered the risk of exposure to T. solium-infected pork. Conclusions: This QMRA showed that there is still a risk of obtaining an infection with T. solium due to consumption of pork, especially when pigs are reared and slaughtered at home, using data of five European countries that reported porcine cysticercosis cases. We propose systematic reporting of cysticercosis cases in slaughterhouses, and in addition molecularly confirming suspected cases to gain more insight into the presence of T. solium in pigs and the risk for humans in Europe. When more data become available, this QMRA model could be used to evaluate human exposure to T. solium in Europe and beyond.

BMC infectious diseases, Mar 13, 2018

The zoonotic parasite Taenia solium is endemic in Angónia district, Tete province, Mozambique, th... more The zoonotic parasite Taenia solium is endemic in Angónia district, Tete province, Mozambique, though the burden of the disease complex is unknown. As part of two cross-sectional studies on human and porcine cysticercosis in the area, unique epidemiological and cost data were collected in Angónia district, Mozambique in 2007. These data provided the basis for the assessment of the societal cost of T. solium in the district, which estimates the impact of the disease on human and pig populations and includes both health and economic approaches in the analysis. Approximately 0.7% (95% Uncertainty Interval (UI), 0.4-0.9) and 0.4% (95% UI, 0.2-0.6) of the total population in the district was estimated to suffer from neurocysticercosis (NCC)-associated epilepsy and headache. The estimated average number of disability-adjusted life years (DALYs) due to NCC-associated epilepsy and headache was 6 (95% UI, 4-8) per thousand persons per year. The total annual costs due to T. solium cysticercos...

Veterinary Parasitology: Regional Studies and Reports, 2017

A cross-sectional study was carried out to determine the prevalence and associated risk factors o... more A cross-sectional study was carried out to determine the prevalence and associated risk factors of parasitic infections in pigs kept under smallholder farming system in Angónia district, Tete Province, Mozambique. A total of 262 pigs from 133 households of six villages were randomly selected. From each pig blood, faecal samples, full body searches, and skin scrapings were conducted to determine the prevalence of Taenia solium (using Ag-ELISA), gastrointestinal (GI) parasites, and ectoparasites respectively. A questionnaire survey was administered to smallholder pig farmers to assess their knowledge and perceptions of health and pig management and an observational study was conducted to determine their pig management practices. The overall prevalence of porcine cysticercosis by Ag-ELISA was 12.6%, GI nematodes 21.4%, Eimeria spp. 8.0% and ectoparasites 37.8%. Four helminths species namely, Metastrongylus spp., Hyostrongylus spp., Oesophagostomum spp., Trichostrongylus spp., were identified from by copro culture, and through faecal egg count, Ascaris suum and Trichuris suis were identified. Haematopinus suis, Rhipicephalus spp. and Echidnophaga gallinacea were found with a prevalence of 32.4%, 7.6%, and 6.9%, respectively. The only significant risk factor identified to be related to the parasite prevalence was pig origin (village), for both gastrointestinal parasites (OR = 10.81[0.81-57.27]) and ectoparasites (OR = 7.06[1.42-35.03]). This study provided evidence that parasitic infections in pigs constitute a major burden for smallholder pig farmers in Angónia district, and that porcine cysticercosis is a public health threat in the area and immediate attention is needed for control and prevention of the parasite.

Acta Tropica, 2017

This study evaluated the effect of mass drug administration (MDA) with praziquantel administered ... more This study evaluated the effect of mass drug administration (MDA) with praziquantel administered to school-aged children (SAC) combined with "track and treat" of taeniosis cases in the general population on the copro-antigen (Ag) prevalence of taeniosis. The study was conducted in 14 villages in Mbozi and Mbeya district, Tanzania. SAC made up 34% of the population and received MDA with praziquantel (40 mg/kg) in 2012 (both districts) and in 2013 (Mbozi only). Three cross

Veterinary parasitology, Jan 20, 2015

Taenia solium taeniasis/cysticercosis is a neglected zoonotic disease complex occurring primarily... more Taenia solium taeniasis/cysticercosis is a neglected zoonotic disease complex occurring primarily in developing countries. Though claimed eradicated from the European Union (EU), an increasing number of human neurocysticercosis cases is being detected. Risk factors such as human migration and movement of pigs/pork, as well as the increasing trend in pig rearing with outside access are discussed in this review. The entry of a tapeworm carrier into the EU seems a lot more plausible than the import of infected pork. The establishment of local transmission in the EU is presently very unlikely. However, considering the potential changes in risk factors, such as the increasing trend in pig farming with outdoor access, the increasing human migration from endemic areas into the EU, this situation might change, warranting the establishment of an early warning system, which should include disease notification of taeniasis/cysticercosis both in human and animal hosts. As currently human-to-hum...

Parasites & vectors, Jan 12, 2015

This study aimed to map the distribution of Taenia solium taeniosis/cysticercosis and the co-dist... more This study aimed to map the distribution of Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa. These two major neglected tropical diseases are presumed to be widely distributed in Africa, but currently the level of co-distribution is unclear. A literature search on T. solium taeniosis/cysticercosis was performed to compile all known studies on the presence of T. solium and apparent prevalence of taeniosis and porcine cysticercosis in Africa. Studies were geo-referenced using an online gazetteer. A Bayesian framework was used to combine the epidemiological data on the apparent prevalence with external information on test characteristics to estimate informed district-level prevalence of taeniosis and porcine cysticercosis. Districts with T. solium taeniosis/cysticercosis presence were cross-referenced with the Global Neglected Tropical Diseases Database for schistosomiasis presence. The search strategies identified 141 reports of T. solium in...

Parasites & Vectors, 2021

Taenia spp. are responsible for a substantial health and economic burden in affected populations.... more Taenia spp. are responsible for a substantial health and economic burden in affected populations. Knowledge of the fate of the eggs of Taenia spp. in the environment and of other factors facilitating the transmission of eggs to intermediate hosts is important for the control/elimination of infections caused by Taenia spp. The aim of this systematic review was to summarize current knowledge of the factors influencing the survival and dispersal of Taenia spp. eggs in the environment. Publications retrieved from international databases were systematically reviewed. Of the 1465 papers initially identified, data were ultimately extracted from 93 papers. The results of this systematic review indicate that survival is favoured at moderate temperatures (0–20 °C). Humidity seems to affect the survival of Taenia spp. eggs more than temperature. Under field circumstances, Taenia spp. eggs have been found to survive for up to 1 year. Taenia spp. eggs are commonly found on vegetables (0.9–30%) a...

Veterinary Parasitology: Regional Studies and Reports, 2020

Taenia solium taeniosis is a growing health problem in large parts of the world including Sub-Sah... more Taenia solium taeniosis is a growing health problem in large parts of the world including Sub-Saharan Africa. Humans are infected by eating undercooked pork with T. solium metacestodes, which cause taeniosis. The aim of the present study was to assess the effect of increasing temperatures on T. solium metacestode viability in pork. Methods: Heavily T. solium infected pieces of pork were cooked in a water-bath at five different temperatures (40°C, 50°C, 60°C, 70°C and 80°C) for 10-60 min. At each temperature/time point, five 5x5x5 cm pieces of pork fitted with thermometers at the core were placed in the water-bath. Controls were kept at 5°C throughout exposure. After exposure, approximately 100 intact metacestodes were harvested and after a maximum of 6 h incubation at 37°C in a culture media consisting of 50% porcine bile and 50% saline, the metacestodes were evaluated for viability. Results: The metacestodes were fully viable after cooking at a core temperature of 40°C for up to an hour. The metacestodes were non-viable after cooking for > 40 min at a core temperature over 50°C. All metacestodes were dead after cooking for 30 min at a core temperature of 60°C; at 70°C, non-viability was found after 20 min and all metacestodes were dead after 10 min cooking at 80°C. Conclusion: Findings showed that pork pieces cooked at > 80°C for > 10 min proved safe for human consumption. This means that dishes consisting of pork pieces in sizes not greater than a 5 cm cube which are immersed in continuously boiling water for at least 10 min would be safe to eat. However, pork deep-fried in oil may entail a risk due to generally shorter cooking time. More research on the cooking practises is needed in order to produce safe guidelines for risk-free pork consumption.

Tropical Animal Health and Production, 2019

Education on pig farming has been recognized as an important method of transferring knowledge and... more Education on pig farming has been recognized as an important method of transferring knowledge and improving production among smallholder pig producers in rural settings, but the effectiveness of this in different rural settings remains unknown. A community-based intervention trial on smallholder pig farmers was conducted with the aim of evaluating the effectiveness of pig farming education. Baseline information was collected using interview-based questionnaires and observations regarding pig welfare and husbandry practices followed by participatory pig farming education and field demonstrations. The study was carried out between May 2014 and May 2016 and involved 90 smallholder pig farmers from six villages in Angónia district, of Tete province in Mozambique. The baseline questionnaire among several aspects regarding pig management highlighted that most farmers had an overall knowledge on aspects of transmission (55.1%) and prevention (48.9%) of African swine fever (ASF), porcine cysticercosis (PC) transmission (8.2%), and field diagnosis (36.7%), and they were not aware of the zoonotic potential of PC or the basic husbandry procedures of pigs kept under permanent confinement. Forty-nine of the 90 farmers enrolled, participated in the pig farming education, which provided the basis for making a comparison between trained (54%) and nontrained (46%) pig farmers. Since knowledge for ASF transmission (P < 0.036), pig pen design (P < 0.014), reasons for confine the pigs (P < 0.016), as well as the adoption of the new introduced pig pen model (P < 0.025), and the practices of acceptable, good hygiene of the pig pen (P < 0.009 and P < 0.014, respectively), improved significantly in both groups, a remarkable spill-over was observed, proving villagers capable of transferring knowledge within the villages. However, water provision and total confinement in both groups were still not practiced by the most farmers following the pig farming education (P > 0.174 and 0.254). It is concluded that despite improved knowledge, the farmers failed to follow several recommendations, most likely due to poverty such as lack of basic resources like food and water, which even the farmers themselves lacked for their day to day living.

Acta Veterinaria Scandinavica, 2019

Toxoplasma gondii is a zoonotic parasite of worldwide importance. In this study, we estimated T. ... more Toxoplasma gondii is a zoonotic parasite of worldwide importance. In this study, we estimated T. gondii seroprevalence in extensively farmed wild boars in Denmark, where little is known about T. gondii in animal hosts. Our study focused on wild boars because they are considered good indicator species for the presence of T. gondii, and wild boar meat is used for human consumption. Serum samples from 101 wild boars collected in 2016-2018 from five different locations from the continental part of Denmark, Jutland, were screened for anti-T. gondii antibodies. The samples were analysed using a commercial indirect enzyme-linked immunosorbent assay (ELISA). Samples from 28 (27.7%) of the 101 wild boars tested positive with the ELISA. The odds for a wild boar to test seropositive were higher if it was sampled during the hunting season 2017-2018 than during 2016-2017 and if it was reported to be at least 1 year old than if it was younger (logistic regression model with the two variables: odds ratios 17.5 and 3.9, respectively). A substantial proportion of the investigated extensively farmed wild boars had been exposed to T. gondii. Moreover, the parasite appeared widespread, at least in the continental part of Denmark, Jutland, as seropositive wild boars were found from all five sampled locations. Assuming seropositivity indicates hosting viable parasites, consumption of undercooked wild boar meat from Denmark is a potential source of T. gondii infections to other hosts, including humans.

Veterinary Parasitology: Regional Studies and Reports, 2018

This study was conducted to evaluate effectiveness of an integrated management intervention in th... more This study was conducted to evaluate effectiveness of an integrated management intervention in the control of endo-and ectoparasites of pigs kept by smallholder farmers in Mbeya Rural and Mbozi districts of southern highlands of Tanzania. A repeated cross-sectional group randomization design was employed, with 10 villages in the intervention group and six villages in the control group. The intervention consisted of improving pig confinement, feeds and feeding practices, and strategic anthelmintic treatment of pigs with oxfendazole, to primarily control Taenia solium (porcine) cysticercosis and nematodes; and with ivermectin to control ectoparasites and nematodes. Blood and faecal samples, ectoparasite specimens and skin scrapings were collected at baseline and two follow-up rounds, at an interval of seven months. A total of 482, 460 and 421 pigs were sampled in 221, 196 and 139 households at baseline, first and second follow-up visits respectively. Sero-prevalence of PC, prevalence and burden of gastrointestinal (GI) nematodes and prevalence of ectoparasites were determined using Ag-ELISA, McMaster faecal egg counting technique and body searches/skin scrapings, respectively. Mann Whitney test was used to measure intervention effect by comparing changes from baseline values of prevalence and faecal egg counts between the two groups. No significant difference (p > 0.05) was observed between the two groups, in changes from baseline of sero-prevalence of PC. The intervention significantly reduced prevalence of Trichuris suis (p = 0.044) and mean faecal egg counts of Ascaris suum (p = 0.02) from baseline to first follow-up. The intervention showed a substantial effect on the prevalence of ectoparasites as it significantly reduced overall prevalence of ectoparasites (p = 0.026), lice (p = 0.045), ticks (p = 0.049) and mites (p = 0.013) from baseline to first follow-up, and prevalence of ectoparasites, lice and mites from baseline to second follow-up (p = 0.052, p = 0.03, p = 0.017 respectively). This study has demonstrated a moderate effect of the intervention on controlling GI nematodes and ectoparasites, but no effect on sero-prevalence of PC. The reported ineffectiveness of the intervention against PC is probably an underestimation because serology is not able to provide quantitative data. It may also be a result of reduced compliance as this was a field study. Nevertheless, further studies are needed to better understand transmission dynamics of PC and explore One Health approaches including treatment of the human population against taeniosis to better secure public health.