Infection with Trypanosoma lewisi or Trypanosoma musculi may promote the spread of Toxoplasma gondii.

Toxoplasma gondii can infect almost all warm-blooded vertebrates with pathogensis being largely influenced by the host immune status. As important epidemiological hosts, rodents are globally distributed and are also commonly found infected with haemoflagellates, such as those in the genus Trypanosoma. We here address whether and how co-infection with trypanosomes can influence T. gondii infection in laboratory models. Rats of five strains, co-infected with T. lewisi and mice of four strains, co-infected with T. musculi, were found to be more or less susceptible to T. gondii infection, respectively, with corresponding increased or decreased brain cyst burdens. Downregulation of iNOS expression and decreased NO production or reverse were observed in the peritoneal macrophages of rats or mice, infected with trypanosomes, respectively. Trypanosoma lewisi and T. musculi can modulate host immune responses, either by enhancement or suppression and influence the outcome of Toxoplasma infection.

Malnutrition as the cause of recumbency in suckler cows associated with Trypanosoma theileri infection.

BACKGROUND: Recumbent cows are a diagnostic challenge because of a wide range of differential diagnoses, which include trauma, neurological and metabolic disorders, malnutrition and mineral deficiencies. This case report describes recumbent suckler cows that presented as a herd problem. In addition to weakness due to inanition, Cu and Se deficiencies were considered as possible aetiologies of the recumbency. Furthermore, Trypanosoma (T.) theileri, a blood parasite of unknown importance in Germany, was detected in the blood of some cows. CASE PRESENTATION: Three recumbent cows were referred to the Clinic for Ruminants and Swine, Faculty of Veterinary Medicine of the University of Leipzig. They were unable to rise and had low body condition scores and rough hair coats. Haematological and serum biochemical analyses showed neutrophilia, electrolyte imbalances, increased activities of muscle and liver enzymes and decreased concentrations of trace elements, especially Copper (Cu) and Selenium (Se). T. theileri was detected in a routine blood smear from one cow. The cows did not respond to an intensive care protocol, which included intravenous fluids and electrolytes, mineral substitution, non-steroidal anti-inflammatories and antibiotics, and were therefore euthanized or died. Postmortem examination showed cachexia, subcutaneous and scleral oedema and muscular dystrophy, especially in the hind limbs. Follow-up examination of the herd of origin produced similar findings including the detection of T. theileri in a large proportion of the herd. Ration analysis revealed considerable undersupply of several nutrients. CONCLUSIONS: Based on all findings, an aetiological diagnosis of trace mineral and nutrient deficiency with possible involvement of T. theileri was made.

Increased Trypanosoma spp. richness and prevalence of haemoparasite co-infection following translocation.

BACKGROUND: Understanding how fauna translocation and antiparasitic drug treatment impact parasite community structure within a host is vital for optimising translocation outcomes. Trypanosoma spp. and piroplasms (Babesia and Theileria spp.) are known to infect Australian marsupials, including the woylie (Bettongia penicillata). However relatively little is known about these haemoparasites, or how they respond to management practices such as translocation. We monitored haemoparasites infecting woylies for up to 12 months during two fauna translocations to supplement existing woylie populations in three different sites (Dryandra, Walcott and Warrup East) within south-western Australia between 2014 and 2016, with the aim of investigating (i) how haemoparasite prevalence, Trypanosoma spp. richness and Trypanosoma spp. community composition varied over time and between different sites following translocation; and (ii) whether ivermectin treatment indirectly impacts haemoparasite prevalence. Using molecular methods, 1211 blood samples were screened for the presence of trypanosomes, and a subset of these samples (n = 264) were also tested for piroplasms. RESULTS: Trypanosomes and piroplasms were identified in 55% and 94% of blood samples, respectively. We identified five Trypanosoma species, two Theileria species, a single species of Babesia and a novel Bodo species. Trypanosoma spp. richness and the prevalence of haemoparasite co-infection increased after translocation. Prior to translocation, Trypanosoma spp. community composition differed significantly between translocated and resident woylies within Walcott and Warrup East, but not Dryandra. Six months later, there was a significant difference between translocated and resident woylies within Dryandra, but not Walcott or Warrup East. The response of haemoparasites to translocation was highly site-specific, with predominant changes to the haemoparasite community in translocated woylies occurring within the first few months following translocation. Ivermectin treatment had no significant effect on haemoparasite prevalence. CONCLUSIONS: This study contributes to our understanding of haemoparasite dynamics in woylies following translocation. The highly site-specific and rapid response of haemoparasites to translocation highlights the need to better understand what drives these effects. Given that haemoparasite prevalence and composition of translocated and resident animals changed significantly following translocation, we propose that parasite monitoring should form an essential component of translocation protocols, and such protocols should endeavour to monitor translocated hosts and cohabiting species.

Indigofera oblongifolia protects against trypanosomiasis-induced spleen injury.

BACKGROUND: Trypanosomiasis is a neglected tropical disease, transmitted by blood-sucking insects and can affect humans and animals, depending on the species of Trypanosoma parasite. Trypanosoma has acquired resistance to the majority of drugs used; hence, alternative medicines are required. Indigofera oblongifolia leaf extract (IOE) has been shown to treat blood stage malaria. Here, IOE was used to demonstrate its effect on Trypanosoma evansi-infected mice. METHODS: Analysis of IOE by gas chromatography-mass spectrometry showed the presence of many active components like flavonoids and phenolics. The mice were divided into three groups as follows: vehicle control, T. evansi-infected mice and T. evansi-infected-treated mice. RESULTS: The findings demonstrate a significant effect of IOE treatment on T. evansi-infected mice. Parasitemia was decreased by 70%, weight loss was reduced, and splenomegaly was significantly decreased. Additionally, IOE improved the histological architecture of the spleen, as shown by the improved histological injury score post-treatment. Anemia was apparent during the course of infection in T. evansi-infected mice; this was reversed upon treatment with IOE to almost the normal level of hemoglobin and erythrocytes. Reduced glutathione and catalase were also ameliorated upon IOE treatment compared to T. evansi-infected mice. CONCLUSION: Overall, this study shows the ameliorative role of IOE against T. evansi-induced spleen injury in mice.

Trypanosoma vivax in water buffalo of the Venezuelan Llanos: An unusual outbreak of wasting disease in an endemic area of typically asymptomatic infections.

Trypanosoma vivax has been associated with asymptomatic infections in African and South American buffalo. In this study, T. vivax was analyzed in water buffalo (Bubalus bubalis) from Venezuela in a molecular survey involving 293 blood samples collected from 2006 to 2015 across the Llanos region. Results demonstrated constant infections (average 23%) during the years analyzed. In general, animals were healthy carriers of T. vivax with low levels of parasitemia and were diagnosed exclusively by TviCATL-PCR. However, an outbreak of severe acute infections mostly in dairy animals was reported during a prolonged drought affecting 30.4% of a buffalo herd (115 animals examined). During the outbreak, animals exhibiting anemia and neurological disorders developed fatal infections, and 7% of the herd died within nine months before treatment against trypanosomosis. Microsatellite locus genotyping (MLG) of T. vivax samples before and during the outbreak revealed similar genotypes, but outbreak isolates exhibited the most divergent MLG. Venezuelan samples from symptomless and sick buffalo did not share the MLGs previously detected in asymptomatic Brazilian buffalo. Trypanosoma evansi was not detected in the herd examined during the outbreak. However, as expected Babesia sp. (62.6%) and Anaplasma sp. (55.6%) infections were highly prevalent in asymptomatic buffalo in the studied areas. This is the first South American outbreak of highly lethal acute T. vivax infections in water buffalo. Our results suggest that chronically infected and asymptomatic buffalo living in areas of enzootic equilibrium can develop symptomatic/lethal disease triggered by stressful scarcity of green forage and water during long droughts, inappropriate management of herds and likely concomitant anaplasmosis and babesiosis. Altogether, these factors weaken buffalo immune defenses, allowing T. vivax to proliferate and, consequently, allowing for progression to wasting disease.

Potential association of reduced cholinesterase activity with Trypanosoma evansi pathogenesis in buffaloes.

The present study aimed to investigate the association of cholinesterase activity with trypanosomosis in buffaloes. Thirty-three clinical cases of trypanosomosis in water buffaloes, found positive for trypomastigotes of T. evansi on blood smear examination, were divided into two groups based on clinical manifestations. Twenty diseased buffaloes revealing only common clinical signs were allocated to Group I, while the remaining 13 buffaloes showing common clinical manifestations along with neurological disturbances were allocated to Group II. Twelve clinically healthy buffaloes, free from any haemoprotozoa infection, were kept as healthy control (Group III). Blood samples were collected from buffaloes of all three groups to determine serum cholinesterase activity. Compared to buffaloes of healthy control group, cholinesterase activity in T. evansi-infected buffaloes of Group I and II was significantly (P<0.001) lower. However, no significant difference was observed in cholinesterase activity between the T. evansi-infected buffaloes exhibiting neurological disorders and no neurological disorders. Summing up, reduced cholinesterase activity seems to be associated with the pathogenesis of natural T. evansi infection and its clinical manifestations in buffaloes possibly by evading immune response. Further studies are warranted on association of cholinesterase activity in T. evansi-infected buffaloes with neurological disorders.

Neuropsychiatric manifestations of some tropical diseases.

Some tropical diseases are the direct cause of severe disturbances of cerebral function while others affect only finer cerebral systems controlling fears, anxiety and personality traits. The mechanisms by which psychiatric symptoms are produced in tropical disorders are not any different from the mechanisms that relate to any physical disorders. Neuropsychiatric symptoms may be caused by a number of different mechanisms including bacterial toxins, release of cytokines, hyperthermia, shock (poor perfusion), acute renal insufficiency, pulmonary failure (shock lung), coagulopathy, disruption of the blood-brain barrier, and/or the nest of pathogens into the central nervous system. The following tropical illnesses can be associated with neuropsychiatric symptoms: neurocysticercosis, malaria, trypanosomiasis, dengue, and schistosomiasis. Neurological and psychiatric impairments induced by tropical diseases both represent a major category of invalidating disorders, which cause profound changes in the nervous system functions, often associated with severe sequels or late-onset disturbances. It is therefore important to disseminate knowledge of the neuropsychiatric symptoms accompanying tropical diseases in order to increase the awareness of these problems and challenges.

Development of a pHrodo-based assay for the assessment of in vitro and in vivo erythrophagocytosis during experimental trypanosomosis.

Extracellular trypanosomes can cause a wide range of diseases and pathological complications in a broad range of mammalian hosts. One common feature of trypanosomosis is the occurrence of anemia, caused by an imbalance between erythropoiesis and red blood cell clearance of aging erythrocytes. In murine models for T. brucei trypanosomosis, anemia is marked by a very sudden non-hemolytic loss of RBCs during the first-peak parasitemia control, followed by a short recovery phase and the subsequent gradual occurrence of an ever-increasing level of anemia. Using a newly developed quantitative pHrodo based in vitro erythrophagocytosis assay, combined with FACS-based ex vivo and in vivo results, we show that activated liver monocytic cells and neutrophils as well as activated splenic macrophages are the main cells involved in the occurrence of the early-stage acute anemia. In addition, we show that trypanosomosis itself leads to a rapid alteration of RBC membrane stability, priming the cells for accelerated phagocytosis.

Effects of iron supplementation on blood adenine deaminase activity and oxidative stress in Trypanosoma evansi infection of rats.

The aim of this study was to assess the effects of iron supplementation on oxidative stress and on the activity of the adenosine deaminase (ADA) in rats experimentally infected by Trypanosoma evansi. For this purpose, 20 rats were divided into four experimental groups with five animals each as follows: groups A and B were composed by healthy animals, while animals from groups C and D were infected by T. evansi. Additionally, groups B and D received two subcutaneous doses of iron (60 mg kg(-1)) within an interval of 5 days. Blood samples were drawn on day 8 post infection in order to assess hematological and biochemical variables. Among the main results are: (1) animals from group C showed reduced erythrogram (with tendency to anemia); however the same results were not observed for group D; this might be a direct effect of free iron on trypanosomes which helped to reduce the parasitemia and the damage to erythrocytes caused by the infection; (2) iron supplementation was able to reduce NOx levels by inhibiting iNOS, and thus, providing an antioxidant action and, indirectly, reducing the ALT levels in groups Band D; (3) increase FRAP levels in group D; (4) reduce ADA activity in serum and erythrocytes in group C; however, this supplementation (5) increased the protein oxidation in groups B and D, as well as group C (positive control). Therefore, iron showed antioxidant and oxidant effects on animals that received supplementation; and it maintained the activity of E-ADA stable in infected/supplemented animals.

Active infection and morphometric study of Trypanosoma evansi among horses in Peninsula Malaysia.

Apart from occasional reports of clinical disease affecting horses, there is no information about Trypanosoma evansi in horses in Peninsula Malaysia. Thus, a cross-sectional study was conducted in eight states in Peninsula Malaysia to determine the active presence of T. evansi in horses. A total of 527 blood samples were obtained and examined by haematocrit centrifugation technique (HCT), Giemsa-stained thin blood smear (GSS), morphometric measurements, polymerase chain reaction (PCR) and cloning of PCR products. The results showed an overall parasitological prevalence of 0.57% (3/527, CI: 1.6-0.19%) with both HCT and GSS. Morphometric study revealed the mean total length of the trypanosomes including the free flagellum was 27.94 ± 2.63 µm. PCR successfully amplified a trypanosome specific 257 bp in 1.14% of samples (6/527, CI: 2.4-0.52%) and was confirmed by nucleotide sequences. The mean packed cell volume (PCV) for the positive cases detected by HCT was lower (23% ± 7.00) compared to the positive cases detected by PCR alone in the state of Terengganu (35% ± 4.73). In conclusion, this study showed T. evansi infection occurred in low frequency in horses in Peninsula Malaysia, and anaemia coincided with parasitaemic animals. PCR is considered as a sensitive diagnostic tool when parasitaemia is undetectable. The slight lengthier mean of parasite and anaemia may indicate a virulent strain of T. evansi circulating throughout the country. Thus, it's highly recommended to shed light on host-parasite relationship for better epidemiological understanding.

Molecular prevalence of Babesia bigemina and Trypanosoma evansi in dairy animals from Punjab, India, by duplex PCR: a step forward to the detection and management of concurrent latent infections.

Specific duplex polymerase chain reaction (PCR) was employed on 411 (386 cattle and 25 buffaloes) blood samples of dairy animals from 9 districts of Punjab, India, for simultaneous detection of Babesia bigemina and Trypanosoma evansi. The results were compared and correlated with conventional Giemsa stained thin blood smear (GSTBS) examination and haematological alterations to know the clinical status and pathogenicity of infections. The Bg3/Bg4 and TR3/TR4 primers were used in duplex PCR for B. bigemina and T. evansi amplified products of 689 bp and 257 bp, respectively. The overall prevalence by duplex PCR was found to be 36.49, 2.43, and 3.41% for T. evansi, B. bigemina, and dual infection, respectively. A more significant difference was observed for dual infection status (P ≤ 0.005) as compared to T. evansi (P ≤ 0.05) and B. bigemina (P ≤ 0.01) among various districts under study. A very low prevalence of T. evansi (0.73%) and B. bigemina (0.48%) was seen by GSTBS. The highly sensitive, specific, and cost-effective duplex PCR was able to detect latent T. evansi and B. bigemina infection in cattle and buffaloes. Haematological evaluation revealed marked pathology in B. bigemina infected group and in dual infected group in contrast to that infected with T. evansi alone.

Livestock trypanosomosis in Uganda: parasite heterogeneity and anaemia status of naturally infected cattle, goats and pigs.

The prevalence and pathogenic effects of trypanosomosis were determined in cattle, goats and pigs reared in Kasese, Jinja and Rakai districts, Uganda; presence of trypanosomes was detected by buffy coat technique (BCT). The overall prevalence of trypanosomosis in cattle was 7.6% (144/1,891), 0.7% in goats (4/573) and 2.3% in pigs (9/386). Internal transcribed spacer 1 (ITS1) of ribosomal DNA polymerase chain reaction was utilised to identify trypanosomes to species level and revealed infections in 108 of the 144 trypanosome-positive cattle while all infected goats and pigs gave amplicons. Trypanosoma vivax was the most prevalent trypanosome species in cattle in single and mixed infections compared to infections involving Trypanosoma congolense and Trypanosoma brucei; in pigs, eight were mixed infections with one single T. vivax infection. No predominant trypanosome species was detected in goats. Anaemia, the main trypanosomosis pathological feature, was investigated by determining packed cell volume (PCV). Mean PCV values by t test in infected individuals were significantly lower than non-infected individuals (P<0.05) for all animal species. However, the proportion of anaemic animals was not significantly different in infected and non-infected individuals. In addition, the percent of infected animals by Fisher's exact test depended on district of origin and species but not sex. These findings show that trypanosomosis is a major cause of anaemia in livestock in endemic areas. Cattle were the major animal species affected by trypanosomosis; similar genotypes of trypanosomes were detected in the three animal species. BCT was more effective than ITS1 rDNA detecting trypanosomes in naturally infected cattle.

Hyperlipidaemia in trypanosomiasis of naturally infected horses: possible cachexia-anorexia syndrome?

Trypanosomiasis caused by Trypanosoma evansi commonly produces wasting disease with signs of emaciation and cachexia mainly at the end stage. The present study was conducted to explore the possible hyperlipaemia or hyperlipidaemia and its association with cachexia-anorexia in equine trypanosomiasis. Out of the fifteen confirmed animals, none of the plasma sample was opaque. There was a significant increase in plasma triglyceride, total cholesterol and blood urea nitrogen and a highly significant increase in low-density lipoprotein (LDL) levels. A mild increase in high-density lipoprotein (HDL) and very low-density lipoprotein levels were observed, while the relative percentage of HDL and LDL was altered with high significance. A moderate increase in triglyceride and highly significant increase in LDL might be the reasons for retention of appetite and lipolysis. Possible protein breakdown and presence of lipolysis might be the reasons for cachexia in equine trypanosomiasis.

Iron metabolism and its relationship to anemia and immune system in Trypanosoma evansi infected rats.

The aim of this study was to evaluate biochemical parameters of iron metabolism in rats experimentally infected with Trypanosoma evansi. To this end, 20 rats (Wistar) were intraperitoneally inoculated with blood containing trypomastigotes 10(6) (Group T) and 12 animals were used as negative control (Group C) and received saline (0.2 mL) through same route. Blood samples were collected by cardiac puncture on day 5 (C5, T5) and 30 (C30, T30) post-inoculation (pi) to perform complete blood count and determination of serum iron, transferrin, ferritin, total and latent iron fixation capacity, transferrin saturation and prohepcidin concentration. Also, bone marrow samples were collected, to perform Pearls staining reaction. Levels of iron, total and latent iron binding capacity and prohepcidin concentration were lower (P<0.05) in infected rats (T5 and T30 groups) compared to controls. On the other hand, levels of transferrin and ferritin were higher when compared to controls (P<0.05). The transferrin saturation increased on day 5 pi, but decreased on day 30 pi. The Pearls reaction showed a higher accumulation of iron in the bone marrow of infected animals in day 5 pi (P<0.01). Infection with T. evansi in rats caused anemia and changes in iron metabolism associated to the peaks of parasitemia. These results suggest that changes in iron metabolism may be related to the host immune response to infection and anemic status of infected animals.

Detection of cross infections by Leishmania spp. and Trypanosoma spp. in dogs using indirect immunoenzyme assay, indirect fluorescent antibody test and polymerase chain reaction.

The aim of this study was to detect cross infections by Leishmania spp. and Trypanosoma spp. using enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test (IFAT) and polymerase chain reaction (PCR). Thus, 408 blood samples were collected from dogs domiciled in Araçatuba Municipality, São Paulo State, Brazil; the dogs were of both sexes, of several breeds and aged 6 months. For Leishmania spp., 14.95% (61 out of 408) of dogs were reactive using IFAT. Positivity was 20.10% (82 out of 408) using ELISA and 29.66% (121 out of 408) using PCR, with significant differences for the sex and age of these animals (p < 0.05). For Trypanosoma spp., antibody occurrence using ELISA was 10.54% (43 out of 408), while PCR indicated 2.45% (10 out of 408) positive dogs. Using IFAT, 10.29% (42 out of 408) of animals were considered positive and only sex showed a significant difference (p < 0.05). In this study, 10.54% (43 out of 408) of animals were seropositive according to ELISA for Trypanosoma spp., of which 79.07% (34 out of 43) showed positive results in the molecular diagnosis for Leishmania spp., while of the 10.29% (42 out of 408) positive dogs according to IFAT, 95.24 % (40 out of 42) had confirmed infection by this parasite. The obtained results demonstrate evidence of cross infections by both protozoa in the animals analysed in this study.

Pathogenic mechanisms of Trypanosoma evansi infections.

Insect-borne diseases exact a high public health burden and have a devastating impact on livestock and agriculture. To date, control has proved to be exceedingly difficult. One such disease that has plagued sub-Saharan Africa is caused by the protozoan African trypanosomes (Trypanosoma species) and transmitted by tsetse flies (Diptera: Glossinidae). This presentation describes Trypanosoma evansi (T. evansi) which causes the disease known as trypanosomosis (Surra) or trypanosomiasis in which several attempts have being made to unravel the clinical pathogenic mechanisms in T. evansi infections, yielding various reports which have implicated hemolysis associated to decrease in life span of erythrocytes and extensive erythrophagocytosis being among those that enjoy prominence. T. evansi generates Adenosine Triphosphate (ATP) from glucose catabolism which is required for the parasite motility and survival. Oxidation of the erythrocytes induces oxidative stress due to free radical generation. Lipid peroxidation of the erythrocytes causes membrane injury, osmotic fragility and destruction of the red blood cell (RBC) making anemia a hallmark of the pathology of T. evansi infections.

Clinical signs and histopathology of brain, spinal cord and muscle of the pelvic limb of rats experimentally infected with Trypanosoma evansi.

The aim of this study was to investigate whether rats infected with Trypanosoma evansi had neurological and locomotor signs, as well as histological lesions in the central nervous system (CNS) and pelvic muscles. To carry out this study, 52 rats were used and divided into two groups. The animals in Group A (n=40) were infected with T. evansi, and the rats in Group B (n=12) were used as negative controls (non-infected). Neurological examination was performed at Days 5, 15, 30 and 150 post-infection (PI) with eventual euthanasia of the rats. Samples of brain, spinal cord and skeletal muscle (biceps femoris and gastrocnemius muscles) were collected. The neurological tests evaluated motor capacity, balance and pain sensitivity. At Day 5 PI in Subgroup A1, the rats showed high parasitemia, became apathetic and presented with slow movements and signs of disorientation. After Day 15 PI in Subgroup A2 and Day 30 PI in Subgroup A3, no more clinical abnormalities were observed. Histologically, there was no damage to the CNS in these three subgroups, but within Subgroup A3, mononuclear infiltration of the muscle was observed. Rats chronically infected (Subgroup A4 - Day 150 PI) showed muscle atrophy, walking dysfunction and paralysis of the hind limbs. Mild mononuclear inflammatory infiltrates and perivascular cuffs were observed in the CNS of some of the animals in Subgroup A4. In these rats, severe muscle damage was observed in the skeletal muscle which included atrophy and loss of muscle fibers, multinucleated giant muscle cells, mononuclear myositis, Wallerian degeneration of the innervating fibers and mononuclear inflammatory infiltrate in the perineurium and adipose tissue. Based upon these findings, we conclude that infection by T. evansi in rats leads to muscle damage, which is probably the cause of the paralysis of hind limbs.

Delta-aminolevulinate dehydratase activity in red blood cells of rats infected with Trypanosoma evansi.

The aim of this study was to evaluate the activity of delta-aminolevulinate dehydratase (δ-ALA-D) in red blood cells of rats infected with Trypanosoma evansi and establish its association with haematocrit, serum levels of iron and zinc and lipid peroxidation. Thirty-six male rats (Wistar) were divided into 2 groups with 18 animals each. Group A was non-infected while Group B was intraperitoneally infected, receiving 7·5×106 trypomastigotes per animal. Each group was divided into 3 subgroups of 6 rats and blood was collected during different periods post-infection (p.i.) as follows: day 5 (A1 and B1), day 15 (A2 and B2) and day 30 PI (A3 and B3). Blood samples were collected by cardiac puncture to estimate red blood cell parameters (RBC), δ-ALA-D activity and serum levels of iron, zinc and thiobarbituric acid reactive substances (TBARS). Rats in group B showed a significant (P<0·05) reduction of RBC count, haemoglobin concentration and haematocrit at days 5 and 15 p.i. The activity of δ-ALA-D in blood was significantly (P<0·001) increased at days 15 and 30 p.i. δ-ALA-D activity in blood had a significant (P<0·05) negative correlation with haematocrit (r=-0·61) and haemoglobin (r=-0·70) at day 15 p.i. There was a significant (P<0·05) decrease in serum iron and zinc levels and an increase in TBARS levels (P<0·05) during infection. The δ-ALA-D activity in blood was negatively correlated with the levels of iron (r=-0·68) and zinc (r=-0·57) on day 30 p.i. It was concluded that the increased activity of δ-ALA-D in blood might have occurred in response to the anaemia in remission as heme synthesis was enhanced.